Interference Cancellation with Time-Varying Interference and/or Distortion

ABSTRACT

A method and apparatus is disclosed to compensate for interference and/or distortion impressed onto a transmitted communications signal in the presence of one or more time-varying conditions. A communications receiver includes a noise analyzer to characterize the composition of the interference and/or distortion impressed onto a transmitted communications signal in the presence of one or more time-varying conditions. The noise analyzer may provide a selection signal indicating the composition of the interference and/or distortion impressed onto a transmitted communications signal in the presence of one or more time-varying conditions to be used by the communications receiver. In an exemplary embodiment, the communications receiver selects at least one set of filter coefficients to compensate for the interference and/or distortion impressed onto a transmitted communications signal in the presence of a particular time-varying interference and/or distortion condition. In another exemplary embodiment, the communications receiver selects a corresponding interference cancellation filter bank to compensate for the interference and/or distortion impressed onto a transmitted communications signal in the presence of the particular time-varying interference and/or distortion condition.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional PatentApplication No. 61/282,165, filed Dec. 23, 2009, and is a continuationin part of U.S. patent application Ser. No. 12/078,923, filed Apr. 8,2008, which claims the benefit of U.S. Provisional Patent ApplicationNo. 60/960,868, filed Oct. 17, 2007, all of which are incorporatedherein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates generally to an interference cancellationfilter and specifically to using the interference cancellation filter tocompensate for interference and/or distortion impressed onto atransmitted communications signal in the presence of time-varyingconditions.

BACKGROUND

A communications system typically involves transmitting a sequence ofdata from a communications transmitter to a communications receiver overa communications channel. The communications transmitter and/or thecommunications receiver may include one or more cable modems, set-topboxes, mobile radios, laptop modems, and/or cellular telephones toprovide some examples. The communications channel may include amicrowave radio link, a satellite channel, a fiber optic cable, or acopper cable to provide some examples. The communications channelcontains a propagation medium that a transmitted communications signalpasses through before reception by the communications receiver. Thepropagation medium of the communications channel introduces interferenceand/or distortion into the transmitted communications signal causing areceived communications signal to differ from the transmittedcommunications signal. The communications channel may introduceadditional interference and/or distortion resulting from undesirablesignals and/or noise into the transmitted communications signal. Thecommunications transmitter and/or the communications receiver mayintroduce further interference and/or distortion into the transmittedcommunications signal causing the received communications signal todiffer from the transmitted communications signal.

Communications systems may use an adjustable filter in the form of aninterference cancellation filter to reduce the effect of theinterference and/or distortion attributable to the communicationschannel, the communications transmitter, and/or the communicationsreceiver. To compensate for this interference and/or the distortion, aconventional interference cancellation filter may adaptively adjust animpulse response by updating interference cancellation filtercoefficients through, for example, a least-squares algorithm, such asthe widely known Least Mean Squared (LMS), Recursive Least Squares(RLS), Minimum Mean Squared Error (MMSE) algorithms or any suitableequivalent algorithm that yields a least-squares result. Alternatively,the conventional interference cancellation filter may employ techniquesdisclosed in

(i) U.S. patent application Ser. No. 10/142,189, filed May 8, 2002,entitled “Cancellation of Interference in a Communication System withApplication to S-CDMA,” now U.S. Pat. No. 7,110,434;

(ii) U.S. patent application Ser. No. 10/242,032, filed Sep. 12, 2002,entitled “Successive Interference Canceling for CDMA,” now U.S. Pat. No.7,190,710;

(iii) U.S. patent application Ser. No. 10/136,059, filed Apr. 30, 2002,entitled “Chip Blanking and Processing in SCDMA to Mitigate Impulse andBurst Noise and/or Distortion,” now U.S. Pat. No. 7,236,545;

(iv) U.S. patent application Ser. No. 10/000,415, filed Nov. 2, 2001,entitled “Detection and Mitigation of Temporary Impairments in aCommunications Channel,” now U.S. Pat. No. 7,308,050;

(v) U.S. patent application Ser. No. 10/962,803, filed Oct. 12, 2004,entitled “Chip Blanking and Processing in SCDMA to mitigate impulse andburst noise and/or distortion,” now U.S. Pat. No. 7,366,258;

(vi) U.S. patent application Ser. No. 11/089,139, filed Mar. 24, 2005,entitled “Cancellation of Burst Noise in a Communication System withApplication to S-CDMA,” now U.S. Pat. No. 7,415,061; and

(vii) U.S. patent application Ser. No. 10/237,853, filed Sep. 9, 2002,entitled “Detection and Mitigation of Temporary (Bursts) Impairments inChannels using SCDMA,” now U.S. Pat. No. 7,570,576, each of which isincorporated herein by reference in its entirety.

These conventional interference cancellation approaches use, in part, ascheme tantamount of time-averaging to determine correlation propertiesof the interference and/or distortion. Commonly, the interference and/ordistortion introduced by the communications channel may include one ormore time-varying conditions. The conventional interference cancellationfilter may not properly determine the correlation properties of theinterference and/or distortion in the presence of the one or moretime-varying conditions. In this situation, the least-squares algorithmor the suitable equivalent may inadequately train the conventionalinterference cancellation filter to compensate for the interferenceand/or distortion. To provide some robustness against time-varyinginterference, conventional cancellation or mitigation techniques haveadded some nonlinear processing to the time-averaging results. Forexample, conventional nonlinear processing may include taking frequencybins with relatively large interference power for a brief time, andholding a higher power value. Still, the result of these conventionaltechniques is a single time-average capture of the interferencecharacteristics, but modified from the true time-average in a manner toprovide robustness against dimensions of interference which occasionallyincur relatively large power. The result of nonlinearly treating thetime-averaging, and introducing larger-than-averaged interferenceestimates in some dimensions, is that when extremely powerfulinterference is present it will be greatly reduced as it appears at adecision point in the receiver. However, typically this processing alsoincurs the property that when the interference is not extreme, the noisepower at a decision point will be increased compared to the noise whichwould be at the decision point with true time-averaging. Thus, whilethese prior techniques have been very successful, still, the solutionprovides robustness in the presence of the occasionally extremeinterference in one or more dimensions, but at the sacrifice of someperformance when one or more of the dimensions is over-protected

Therefore, what is needed is an interference cancellation filter that iscapable of compensating for the interference and/or distortion in thepresence of the one or more time-varying conditions, without incurring apenalty when the interference is benign.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

The present invention is described with reference to the accompanyingdrawings. In the drawings, like reference numbers indicate identical orfunctionally similar elements. The left most digit(s) of a referencenumber identifies the drawing in which the reference number firstappears.

FIG. 1 illustrates a block diagram of a communications environmentaccording to an exemplary embodiment of the present invention.

FIG. 2 illustrates a communications channel of the communicationsenvironment according to an exemplary embodiment of the presentinvention.

FIG. 3 illustrates a first block diagram of the communications receiverused in the communications environment according to a first exemplaryembodiment of the present invention.

FIG. 4A illustrates a first block diagram of a noise analyzer used inthe communications receiver according to a first exemplary embodiment ofthe present invention.

FIG. 4B illustrates a second block diagram of the noise analyzer used inthe communications receiver according to a second exemplary embodimentof the present invention.

FIG. 4C illustrates a third block diagram of the noise analyzer used inthe communications receiver according to a third exemplary embodiment ofthe present invention.

FIG. 5A illustrates a first block diagram of a coefficient generatorused in the communications receiver according to a first exemplaryembodiment of the present invention.

FIG. 5B illustrates a second block diagram of the coefficient generatorused in the communications receiver according to a second exemplaryembodiment of the present invention.

FIG. 6 illustrates a first block diagram of an interference cancellationfilter used in the communications receiver according to a firstexemplary embodiment of the present invention.

FIG. 7A illustrates a first block diagram of a vector despreading moduleused in the interference cancellation filter according to a firstexemplary embodiment of the present invention.

FIG. 7B illustrates a second block diagram of a vector despreadingmodule used in the interference cancellation filter according to asecond exemplary embodiment of the present invention.

FIG. 8A illustrates a second block diagram of the interferencecancellation filter used in the communications receiver according to asecond exemplary embodiment of the present invention.

FIG. 8B illustrates a third block diagram of the interferencecancellation filter used in the communications receiver according to athird exemplary embodiment of the present invention.

FIG. 8C illustrates a fourth block diagram of the interferencecancellation filter used in the communications receiver according to afourth exemplary embodiment of the present invention.

FIG. 9 illustrates a second block diagram of the communications receiverused in the communications environment according to a second exemplaryembodiment of the present invention.

FIG. 10A illustrates a first block diagram of the interferencecancellation filter used in the second communications receiver accordingto a first exemplary embodiment of the present invention.

FIG. 10B illustrates a second block diagram of the interferencecancellation filter used in the second communications receiver accordingto a second exemplary embodiment of the present invention.

FIG. 10C illustrates a third block diagram of the interferencecancellation filter used in the second communications receiver accordingto a third exemplary embodiment of the present invention.

FIG. 11 is a flowchart of exemplary operational steps of a noiseanalyzer according to an aspect of the present invention.

The present invention will now be described with reference to theaccompanying drawings. In the drawings, like reference numbers generallyindicate identical, functionally similar, and/or structurally similarelements. The drawing in which an element first appears is indicated bythe leftmost digit(s) in the reference number.

DETAILED DESCRIPTION OF THE INVENTION

The following Detailed Description refers to accompanying drawings toillustrate exemplary embodiments consistent with the present invention.References in the Detailed Description to “one exemplary embodiment,”“an exemplary embodiment,” “an example exemplary embodiment,” etc.,indicate that the exemplary embodiment described may include aparticular feature, structure, or characteristic, but every exemplaryembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same exemplary embodiment. Further, when a particularfeature, structure, or characteristic is described in connection with anexemplary embodiment, it is within the knowledge of those skilled in therelevant art(s) to effect such feature, structure, or characteristic inconnection with other exemplary embodiments whether or not explicitlydescribed.

The exemplary embodiments described herein are provided for illustrativepurposes, and are not limiting. Other exemplary embodiments arepossible, and modifications may be made to the exemplary embodimentswithin the spirit and scope of the present invention. Therefore, theDetailed Description is not meant to limit the present invention.Rather, the scope of the present invention is defined only in accordancewith the following claims and their equivalents.

The following Detailed Description of the exemplary embodiments will sofully reveal the general nature of the present invention that otherscan, by applying knowledge of those skilled in relevant art(s), readilymodify and/or adapt for various applications such exemplary embodiments,without undue experimentation, without departing from the spirit andscope of the present invention. Therefore, such adaptations andmodifications are intended to be within the meaning and plurality ofequivalents of the exemplary embodiments based upon the teaching andguidance presented herein. It is to be understood that the phraseologyor terminology herein is for the purpose of description and not oflimitation, such that the terminology or phraseology of the presentspecification is to be interpreted by those skilled in relevant art(s)in light of the teachings herein.

Communications Environment

FIG. 1 illustrates a block diagram of a communications environmentaccording to an exemplary embodiment of the present invention. Thecommunications environment 100 includes a communications transmitter 102to transmit a one or more sequences of data 150 as received from one ormore transmitter user devices to a communications receiver 106 via acommunications channel 104. The one or more transmitter user devices mayinclude, but are not limited to, personal computers, data terminalequipment, telephony devices, mobile communication devices, broadbandmedia players, personal digital assistants, software applications, orany other device capable of transmitting and/or receiving data.

The communications transmitter 102 provides a transmitted communicationssignal 152 based on the one or more sequences of data 150. Thetransmitted communications signal 152 may include a time divisionmultiple access (TDMA) communications signal, an orthogonal frequencydivision multiplexed (OFDM) communications signal, a synchronous codedivision multiple access (SCDMA) communications signal, any othercommunications signal that includes orthogonal signaling dimensions, orany combination thereof. The transmitted communications signal 152 mayadditionally include active signaling dimensions, inactive signalingdimensions, or any combination of active and inactive signalingdimensions. The active signaling dimensions represent one or moresignaling dimensions of the transmitted communications signal 152 thatinclude information for communication, such as a representation of atleast some of the one or more sequences of data 150 to provide anexample, whereas the inactive signaling dimensions represent one or moresignaling dimensions of the transmitted communications signal 152 thatdoes not include the information for communication. The inactivesignaling dimensions may contain significant power, such as pilots orpreambles to provide some examples. Alternatively, the inactivesignaling dimensions may represent one or more signaling dimensions ofthe transmitted communications signal 152 that include traces of theinformation for communication, that is, greatly diminished in power. Inan exemplary embodiment, the active signaling dimensions (or vectors orwaveforms) and/or inactive signaling dimensions are substantiallyorthogonal; however, they are not required to be absolutely orthogonal.It should be noted that any indexing or numbering associated with theinactive signaling dimensions and/or active signaling dimensions usedherein is arbitrary, those skilled in the relevant art(s) may implementthe indexing or numbering of the signaling dimensions differentlywithout departing from the spirit and scope of the present invention.For example, the active signaling dimensions and the inactive signalingdimensions may be interspersed for a given numbering scheme. As anotherexample, the active signaling dimensions and the inactive signalingdimensions may also vary between communications. In other words, thecommunications transmitter 102 may vary which ones of the signalingdimensions are active signaling dimensions and inactive signalingdimensions within the transmitted communications signal 152.

The transmitted communications signal 152 passes through thecommunications channel 104 to provide a received communications signal154. The communications channel 104 may include, but is not limited to,a microwave radio link, a satellite channel, a fiber optic cable, ahybrid fiber optic cable system, or a copper cable to provide someexamples. The communications channel 104 contains a propagation mediumthat the transmitted communications signal 152 passes through beforereception by the communications receiver 106. The propagation medium ofthe communications channel 104 as well as the communications transmitter102 and/or the communications receiver 106 may introduce interferenceand/or distortion into the transmitted communications signal 152 causingthe received communications signal 154 to differ from the transmittedcommunications signal 152.

The communications receiver 106 observes the received communicationssignal 154 as it passes through the communications channel 104. Similarto the transmitted communications signal 152, the receivedcommunications signal 154 may include active signaling dimensions,inactive signaling dimensions, or any combination active and inactivesignaling dimensions. The communication receiver 106 observes the activesignaling dimensions and/or the inactive signaling dimensions of thereceived communications signal 154 to observe the interference and/ordistortion impressed upon the transmitted communications signal 152. Inan exemplary embodiment, the communication receiver 106 only observesthe inactive signaling dimensions of the received communications signal154 to observe the interference and/or distortion embedded within thetransmitted communications signal 152.

The communications receiver 106 compensates for the interference and/ordistortion impressed upon the transmitted communications signal 152 inthe presence of one or more time-varying conditions. The communicationsreceiver 106 then determines a most-likely transmitted sequence ofmodulation symbols of the transmitted communications signal 152 toprovide one or more sequences of recovered data 156. The one or moresequences of recovered data 156 is provided to one or more receiver userdevices such as, but not limited to, personal computers, data terminalequipment, telephony devices, mobile communication devices, broadbandmedia players, personal digital assistants, software applications, orany other device capable of transmitting and/or receiving data.

As will be understood by persons skilled in the relevant art(s) from theteachings provided herein, the communications transmitter 102 and/or thecommunications receiver 106 may be readily implemented in hardware,software, or a combination of hardware and software. For example, basedon the teachings provided herein, those skilled in the relevant art(s)may implement the communications transmitter 102 and/or thecommunications receiver 106 via a combination of one or more applicationspecific integrated circuits and a processor core for implementingsoftware commands stored in one or more memories. However, this exampleis not limiting, and other implementations are within the scope andspirit of the present invention.

FIG. 2 illustrates a communications channel of the communicationsenvironment according to an exemplary embodiment of the presentinvention. A communications system 200 includes the communicationstransmitter 102 to transmit the transmitted communications signal 152 tothe communications receiver 106 via the communications channel 104.

As shown in FIG. 2, the communications channel 104 may be approximated,in part, by a summation module 202, a summation module 204, and asummation module 206. The summation module 202 embeds an interference252 resulting from the communications transmitter 102 within thetransmitted communications signal 152. Likewise, the summation module204 embeds an interference 254 resulting from the communications channel104 within transmitted communications signal 152. Similarly, thesummation module 206 embeds an interference 256 resulting from thecommunications receiver 106 within the transmitted communications signal152. Herein, a reference to interference and/or distortion refers to anycombination of the interference 252, the interference 254, and/or theinterference 256.

Although not shown in FIG. 2, the interference and/or distortion, asdiscussed above, may additionally include other noise(s) and/ordistortion(s), such as linear filtering distortion to provide anexample, and/or other non-linear noise(s) and/or other non-lineardistortion (s) that may not be additive in nature. For example, theinterference and/or distortion may include one or more time-varyingconditions such that the interference and/or distortion, in itsentirety, may be time-varying. In this situation, the interferenceand/or distortion is not stationary, rather statistics of theinterference and/or distortion vary with time. For instance, theinterference and/or distortion may include a narrowband, high poweredcomponent having a lesser duty cycle and a wider band, lower powercomponent having a greater duty cycle. Because of the lesser duty cycle,the narrowband, high powered component represents a time-varyingcondition by only contributing to the interference and/or distortion fora relatively short duration in time as compared to the wider band, lowerpower component having the greater duty cycle.

Referring back to FIG. 1, the communications receiver 106 may include aninterference cancellation filter to increase an ability of thecommunications receiver 106 to determine the most-likely transmittedsequence of modulation symbols of the transmitted communications signal152. A conventional interference cancellation filter adaptively adjustsan impulse response by updating a set of interference cancellationfilter coefficients to compensate for the interference and/ordistortion. However, a conventional interference cancellation filteruses a scheme tantamount of time-averaging to determine correlationproperties of the interference and/or distortion embedded within thetransmitted communications signal 152. As a result, the conventionalinterference cancellation filter may not adequately update the set ofinterference cancellation filter coefficients when the interferenceand/or distortion includes the one or more time-varying conditions. Forexample, the conventional interference cancellation filter may notadequately compensate for the narrowband, high powered component havingthe lesser duty cycle in the presence of the wider band, lower powercomponent having the greater duty cycle. In this situation, the widerband, lower power component having the greater duty cycle may mask thenarrowband, high powered component having the lesser duty cycle.

First Exemplary Communications Receiver

FIG. 3 illustrates a first block diagram of the communications receiverused in the communications environment according to a first exemplaryembodiment of the present invention. A communications receiver 300observes the received communications signal 154 as it passes through thecommunications channel 104. The received communications signal 154 mayinclude the interference and/or distortion including the one or moretime-varying conditions. For example, the one or more time-varyingconditions may include a first interference and/or distortion conditioncorresponding to the narrowband, high powered component having thelesser duty cycle, a second interference and/or distortion conditioncorresponding to the wider band, lower power component having thegreater duty cycle and/or a third interference and/or distortioncondition corresponding to both the narrowband, high powered componentand the wider band, lower power component. The communications receiver300 compensates for the interference and/or distortion impressed ontothe transmitted communications signal 152 in the presence of the one ormore time-varying conditions. The communications receiver 300 mayrepresent an exemplary embodiment of the communications receiver 106.

The communication receiver 300 may observe the one or more inactivesignaling dimensions of the received communications signal 154 tocompensate for the interference and/or distortion impressed upon thetransmitted communications signal 152 in the presence of the one or moretime-varying conditions. The inactive signaling dimensions of thereceived communications signal 154 represent one or more signalingdimensions of the transmitted communications signal 152 that do notinclude information for communication, but may contain pilots orpreambles, and/or one more signaling dimensions of the transmittedcommunications signal 152 that include the information for communicationbut greatly diminished in power. Alternatively, the communicationstransmitter 102 may momentarily inactivate the active signalingdimensions of the transmitted communications signal 152 such that theactive signaling dimensions of the received communications signal 154are, in effect, inactive signaling dimensions. The communicationsreceiver 106 assesses its effectiveness at reducing the interferenceand/or distortion impressed upon the transmitted communications signal152 in the presence of the one or more time-varying conditions bycomparing a signal metric of one or more of the inactive signalingdimensions of the received communications signal 154 before and afterthe application of an interference canceling operation, such asdisclosed in U.S. patent application Ser. No. 10/000,415, filed Nov. 2,2001, entitled “Detection and Mitigation of Temporary Impairments in aCommunications Channel,” now U.S. Pat. No. 7,308,050, which isincorporated herein by reference in its entirety. The comparison of thesignal metric provides a measure of cancellation of the interferenceand/or distortion without the presence of the information forcommunication. Such comparison may be made for one or multiple sets ofthe interference cancellation filter coefficients to determine which ofthe one or more time-varying conditions are present or dominant.Additionally, this comparison may reveal if a completely new oradditional set of the interference cancellation filter coefficientsneeds to be characterized that is better suited to compensate for theinterference and/or distortion.

Alternatively, the communication receiver 106 may observe one or moreactive signaling dimensions of the received communications signal 154 tocompensate for the interference and/or distortion impressed upon thetransmitted communications signal 152 in the presence of the one or moretime-varying conditions. The active signaling dimensions of the receivedcommunications signal 154 represent one or more signaling dimensions ofthe transmitted communications signal 152 that include the informationfor communication. The communications receiver 106 operates on theactive signaling dimensions to mitigate or reduce, i.e., cancel, theinterference and/or distortion impressed upon the transmittedcommunications signal 152 in the presence of the one or moretime-varying conditions to provide estimates of the transmittedcommunications signal 152. The communications receiver 106 may use theestimates of the information for communication to substantially reducethe information for communication from the active signaling dimensionsof the received communications signal 154 to allow the communicationsreceiver 106 to carry out the operations of the communications receiver106, as discussed above, as if the active signaling dimensions of thereceived communications signal 154 are, in fact, inactive signalingdimensions. The communications receiver 106 may additionally update oneor more sets of the interference cancellation filter coefficients usedto compensate for the interference and/or distortion impressed upon thetransmitted communications signal 152 to further reduce the interferenceand/or distortion impressed upon the transmitted communications signal152 in the presence of the one or more time-varying conditions. Thecommunications receiver 106 assesses its effectiveness at reducing theinterference and/or distortion impressed upon the transmittedcommunications signal 152 in the presence of the one or moretime-varying conditions by comparing the signal metric of one or more ofthe active signaling dimensions of the received communications signal154 before and after the application of an interference cancelingoperation. The comparison of the signal metric provides a measure ofcancellation of the interference and/or distortion with the presence ofthe information for communication substantially removed. Such comparisonmay be made for one or multiple sets of the interference cancellationfilter coefficients to determine which of the one or more time-varyingconditions are present or dominant. Additionally, this comparison mayreveal if a completely new or additional set of the interferencecancellation filter coefficients needs to be characterized that isbetter suited to compensate for the interference and/or distortion.

As shown in FIG. 3, the communications receiver 300 includes acommunications tuner 302, an interference cancellation filter 304, aforward error correction (FEC) decoder 306, a noise analyzer 308, and acoefficient generator 310. The communications tuner 302 operates uponthe received communications signal 154 to provide a noisy sequence ofdata 350. For example, the communications tuner 302 may frequencytranslate or downconvert and/or demodulate the received communicationssignal 154 to a baseband frequency, an intermediate frequency (IF), orany other suitable frequency using a suitable downconversion processthat will be apparent to those skilled in the art(s). The communicationstuner 302 may additionally perform functions such as, but not limitedto, timing recovery, frequency estimation, carrier and/or phaserecovery, automatic gain control (AGC) and/or any other parameterestimation of the received communications signal 154 that will beapparent to those skilled in the art(s). The noisy sequence of data 350includes the active signaling dimensions and/or the inactive signalingdimensions including the interference and/or distortion having the oneor more time-varying conditions. The one or more time-varying conditionsmay include the first time-varying condition, and/or the secondtime-varying condition as discussed above. However, this example is notlimiting, those skilled in the relevant art(s) will recognize that thenoisy sequence of data 350 may include the active signaling dimensionsand/or the inactive signaling dimensions including the interferenceand/or distortion resulting from different time-varying conditionswithout departing from the spirit and scope of the present invention.

The interference cancellation filter 304 compensates for theinterference and/or distortion in the presence of the one or moretime-varying conditions embedded in the active signaling dimension ofthe noisy sequence of data 350 to provide a noise compensated sequenceof data 352. More specifically, the interference cancellation filter 304compensates for the interference and/or distortion in:

1. the absence of the first time-varying condition and the secondtime-varying condition;

2. the presence of the first time-varying condition;

3. the presence of the second time-varying condition; and/or

4. the presence of the first time-varying condition and the secondtime-varying condition.

However, these examples are not limiting, those skilled in the relevantart(s) will recognize that the interference cancellation filter 304 maycompensate for the interference and/or distortion in other time-varyingconditions in accordance with the teachings herein without departingfrom the spirit and scope of the present invention.

The interference cancellation filter 304 then adaptively adjusts animpulse response based upon filter weighting coefficients 358 tocompensate for the interference and/or distortion embedded in the activesignaling dimension of the noisy sequence of data 350 in the presence ofthe one or more time-varying conditions.

The interference cancellation filter 304 additionally provides aninterference cancellation filter information signal 360 based on theactive signaling dimensions of the noisy sequence of data 350 to thenoise analyzer 308 and/or the coefficient generator 310. Theinterference cancellation filter information signal 360 may includesignal parameters such as an average power within a bandwidth of thetransmitted communications signal 152 over a time interval, a slicererror, a bit error rate (BER), a symbol error rate (SER), a signal tonoise ratio (SNR), power in each active signaling dimension, power ineach inactive signaling dimension, usually after removal of any pilot orpreamble if present, average power in all active signaling dimensions,average power in all inactive signaling dimensions, average power in aplurality of dimensions, ranked power in all active signaling dimensionsor derivative thereof (such as largest, top three largest, etc.), rankedpower in all inactive signaling dimensions or derivative thereof, anychannel fidelity metric such as disclosed in U.S. patent applicationSer. No. 10/000,415, filed Nov. 2, 2001, entitled “Detection andMitigation of Temporary Impairments in a Communications Channel,” nowU.S. Pat. No. 7,308,050, which is incorporated herein by reference inits entirety, or any other suitable signal parameter that will beapparent to those skilled in the relevant art(s).

The forward error correction (FEC) decoder 306 may substantially correctfor errors in the active signaling dimensions of the noise compensatedsequence of data 352 using any suitable decoding scheme to provide theone or more sequences of recovered data 156. The decoding scheme mayinclude a block decoding scheme, such as Reed-Solomon decoding, aconvolutional decoding scheme, such as the Viterbi algorithm, aconcatenated decoding scheme involving inner and outer codes, decodingschemes using iterative decoding, partial decoding, iterative decodinginvolving iterations between channel estimation and partial decoding andfull decoding with impulse or burst noise and/or noise unequallydistributed among the signaling dimensions such as colored noise, and/orany other suitable decoding scheme that will be apparent to thoseskilled in the art(s). In an exemplary embodiment, the FEC decoder isoptional. In this exemplary embodiment, the interference cancellationfilter 304 may directly generate the one or more sequences of recovereddata 156.

The FEC decoder 306 additionally provides a decoder information signal362 based on the active signaling dimension of the noise compensatedsequence of data 352 to the noise analyzer 308 and/or the coefficientgenerator 310. The decoder information signal 362 may include signalparameters such as code information, state information, symbols or bitswhich are determined to be incorrect or questionable, likely correctedvalues for such symbols or bits, probabilities for suggested correctionsor a multiplicity of possible choices for a correction, likelihoodmetrics related to estimated signal fidelity corresponding to a segmentof the noise compensated sequence of data 352, or any other suitablesignal parameter that will be apparent to those skilled in the relevantart(s). As another example the decoder information signal 362 mayrepresent a decoder metric such as is disclosed in U.S. patentapplication Ser. No. 10/000,415, filed Nov. 2, 2001, entitled “Detectionand Mitigation of Temporary Impairments in a Communications Channel,”now U.S. Pat. No. 7,308,050 and U.S. patent application Ser. No.10/237,853, filed Sep. 9, 2002, entitled “Detection and Mitigation ofTemporary (Bursts) Impairments in Channels using SCDMA,” now U.S. Pat.No. 7,570,576, each of which is incorporated herein by reference in itsentirety. This FEC decoder metric can provide information. For example,a large number of bit or symbol errors, or large path metric, indicatesa great deal of noise and/or distortion and/or error; in addition otherindicators include too many errors to decode and too many iterations todecode. Any and/or all of these may indicate a less favorable hypothesisfor matching the interference, and suggest that a different hypothesis,or a new hypothesis, be implemented for processing the distorted and/ornoisy signal.

The noise analyzer 308 analyzes the interference and/or distortionimpressed onto the inactive signaling dimensions of the noisy sequenceof data 350 using one or more of the inactive signaling dimensions ofthe noisy sequence of data 350, the interference cancellation filterinformation signal 360, and/or the decoder information signal 362 toprovide the modified sequence of data 354. The noise analyzer 308spectrally characterizes and/or spectrally modifies the inactivesignaling dimensions of the noisy sequence of data 350 to provide themodified sequence of data 354.

The noise analyzer 308 additionally analyzes the interference and/ordistortion impressed onto the inactive signaling dimensions of the noisysequence of data 350 to provide a filter coefficient selection signal356. The noise analyzer 308 characterizes a composition of theinterference and/or distortion embedded within the inactive signalingdimensions of the noisy sequence of data 350 to provide an indication ofthe respective set of filter weighting coefficients that correspondswith the composition of the interference and/or distortion as the filtercoefficient selection signal 356. For example, the noise analyzer 308may characterize the interference and/or distortion embedded within theinactive signaling dimensions of the noisy sequence of data 350 as:

1. not including the first time-varying condition and the secondtime-varying condition the noise analyzer 308 provides the filtercoefficient selection signal 356 indicative of the absence of the firsttime-varying condition and the second time-varying condition;

2. including the first time-varying condition, the noise analyzer 308provides the filter coefficient selection signal 356 indicative of thepresence of the first time-varying condition;

3. including the second time-varying condition, the noise analyzer 308provides the filter coefficient selection signal 356 indicative of thepresence of the second time-varying condition; and/or

4. including the first time-varying condition and the secondtime-varying condition, the noise analyzer 308 provides the filtercoefficient selection signal 356 indicative of the presence of the firsttime-varying condition and the second time-varying condition.

However, these examples are not limiting, those skilled in the relevantart(s) will recognize that the noise analyzer 308 may characterize theinterference and/or distortion embedded within the inactive signalingdimensions of the noisy sequence of data 350 as including othertime-varying conditions in accordance with the teachings herein withoutdeparting from the spirit and scope of the present invention.

The coefficient generator 310 includes one or more sets of filterweighting coefficients for use by the interference cancellation filter304. The coefficient generator 310 determines which one of the one ormore sets of filter weighting coefficients corresponds to thecomposition of the interference and/or distortion based upon one or moreof the filter coefficient selection signal 356, the interferencecancellation filter information signal 360, and/or the decoderinformation signal 362. The coefficient generator 310 may provide arespective set of filter weighting coefficients that corresponds withthe composition of the interference and/or distortion as the filterweighting coefficients 358. The coefficient generator 310 mayadditionally train or update the respective set of filter weightingcoefficients in accordance with a weight computation algorithm. Forexample, the coefficient generator 310 may provide:

1. a first set of filter weighting coefficients corresponding to theabsence of the first time-varying condition and the second time-varyingcondition when the filter coefficient selection signal 356, theinterference cancellation filter information signal 360, and/or thedecoder information signal 362 indicate the first time-varying conditionand the second time-varying condition is absent from the noisy sequenceof data 350;

2. a second set of filter weighting coefficients corresponding to thepresence of the first time-varying condition when the filter coefficientselection signal 356, the interference cancellation filter informationsignal 360, and/or the decoder information signal 362 indicate the firsttime-varying condition is present in the noisy sequence of data 350;

3. a third set of filter weighting coefficients corresponding to thepresence of the second time-varying condition when the filtercoefficient selection signal 356, the interference cancellation filterinformation signal 360, and/or the decoder information signal 362indicate the second time-varying condition is present in the noisysequence of data 350; and/or

4. a fourth set of filter weighting coefficients corresponding to thepresence of the first time-varying condition and the second time-varyingcondition when the filter coefficient selection signal 356, theinterference cancellation filter information signal 360, and/or thedecoder information signal 362 indicate the first time-varying conditionand the second time-varying condition is present in the noisy sequenceof data 350.

However, these examples are not limiting, those skilled in the relevantart(s) will recognize that the coefficient generator 310 may provideother sets of filter weighting coefficients corresponding to othertime-varying conditions in accordance with the teachings herein withoutdeparting from the spirit and scope of the present invention.

Noise Analyzer of the First Exemplary Communications Receiver

Noise Analysis of Signal Dimensions

FIG. 4A illustrates a first block diagram of a noise analyzer used inthe communications receiver according to a first exemplary embodiment ofthe present invention. A noise analyzer 400 spectrally characterizesand/or spectrally modifies the noisy sequence of data 350 to provide themodified sequence of data 354. The noise analyzer 400 additionallyanalyzes the interference and/or distortion impressed onto the noisysequence of data 350 to provide the filter coefficient selection signal356. The noise analyzer 400 characterizes a composition of theinterference and/or distortion embedded within the noisy sequence ofdata 350 and provides an indication of the respective set of filterweighting coefficients that corresponds with the composition of theinterference and/or distortion the filter coefficient selection signal356. The noise analyzer 400 may represent an exemplary embodiment of thenoise analyzer 308.

In this exemplary embodiment, the noise analyzer 400 analyzes theinterference and/or distortion impressed onto one or more of thesignaling dimensions, such as codes, tones, and/or timeslots to providesome examples, of the noisy sequence of data 350. The signalingdimensions may include active signaling dimensions, inactive signalingdimensions, or any combination of active and inactive signalingdimensions. The noise analyzer 400 includes a sampling module 402, aspectral characterization module 404, a modify spectral characterizationmodule 406, and an interference and/or distortion characterizationmodule 408.

The sampling module 402 may sample one or more of the inactive signalingdimensions to provide the sampled sequence of data 450. Alternatively,the sampling module 402 may sample one or more of the active signalingdimensions to provide the sampled sequence of data 450. In thissituation, the information for communication, i.e., data is present inthe active signaling dimensions during sampling. The data, or at least aportion of the data, however, is removed from the sampled sequence ofdata 450 by the sampling module 402 using the interference cancellationfilter information signal 360 and/or the decoder information signal 362.For example, estimates of the data within the active signalingdimensions may be used to effectively reduce the data within the activesignaling such that these active signaling dimensions may be treated asinactive signaling dimensions. As a result, the active signalingdimensions of the noisy sequence of data 350 are, in effect, inactivesignaling dimensions. In an additional alternate, the sampling module402 may sample any combination of the inactive signaling dimensions andthe active signaling dimensions to provide the sampled sequence of data450. The sampling module 402 may additionally despread, mix, and/ordemodulate each of the signaling dimensions prior to sampling.

The spectral characterization module 404 spectrally characterizes thesampled sequence of data 450 to provide a spectral characterization 452.More specifically, the spectral characterization module 404 mayspectrally characterize the inactive signaling dimensions to provide thespectral characterization 452. The spectral characterization module 404may provide any suitable statistical metric of the signaling dimensionsthat will be apparent to those skilled in the relevant art(s) as thespectral characterization 452.

The spectral characterization module 404 additionally provides aspectral characterization information signal 454 based on the sampledsequence of data 450 to communicate information regarding the sampledsequence of data 450, the spectral characterization 452, and/or anysuitable information acquired while determining the spectralcharacterization 452 that will be apparent to those skilled in therelevant art(s) to the interference and/or distortion characterizationmodule 408. The spectral characterization information signal 454 mayinclude statistical metrics of the signaling dimensions that will beapparent to those skilled in the relevant art(s).

The modify spectral characterization module 406 modifies the spectralcharacterization 452 to provide the modified sequence of data 354. Themodify spectral characterization module 406 may raise the noise floor,introduce spectral characteristics that relate to previously presentinterference and/or distortion, introduce spectral characteristics ofexpected interference and/or distortion that are expected but that havenot recently been present (or at all been present), and other preemptivemodifications that will be apparent to those skilled in the relevantart(s).

The modify spectral characterization module 406 additionally provides amodified spectral characterization information signal 456 based on thespectral characterization 452 to communicate information regarding thespectral characterization 452, the modified sequence of data 354 and/orany suitable information acquired while modifying the spectralcharacterization 452 to the interference and/or distortioncharacterization module 408. The modified spectral characterizationinformation signal 456 may include statistical metrics such as a noisefloor power level, spectral characteristics that relate to previouslypresent interference and/or distortion, spectral characteristics ofexpected interference and/or distortion that are expected but that havenot recently been present (or at all been present), and any othersuitable time-domain statistical parameter that will be apparent tothose skilled in the relevant art(s).

The interference and/or distortion characterization module 408 analyzesthe interference and/or distortion impressed onto the inactive signalingdimensions of the noisy sequence of data 350 based upon at least one ofthe interference cancellation filter information signal 360, the decoderinformation signal 362, the spectral characterization information signal454, and/or the modified spectral characterization information signal456 to provide the filter coefficient selection signal 356. Theinterference and/or distortion characterization module 408 characterizesthe composition of the interference and/or distortion embedded withinthe inactive signaling dimensions of the noisy sequence of data 350using this information and provides the indication of the respective setof filter weighting coefficients that corresponds with the compositionof the interference and/or distortion as the filter coefficientselection signal 356. For example, when the interference and/ordistortion characterization module 408 characterizes the interferenceand/or distortion embedded within the inactive signaling dimensions ofthe noisy sequence of data 350 as:

1. not including the first time-varying condition and the secondtime-varying condition, the interference and/or distortioncharacterization module 408 provides the filter coefficient selectionsignal 356 indicative of the absence of the first time-varying conditionand the second time-varying condition;

2. including the first time-varying condition, the interference and/ordistortion characterization module 408 provides the filter coefficientselection signal 356 indicative of the presence of the firsttime-varying condition;

3. including the second time-varying condition, the interference and/ordistortion characterization module 408 provides the filter coefficientselection signal 356 indicative of the presence of the secondtime-varying condition; and/or

4. including the first time-varying condition and the secondtime-varying condition, the interference and/or distortioncharacterization module 408 provides the filter coefficient selectionsignal 356 indicative of the presence of the first time-varyingcondition and the second time-varying condition.

Noise Analysis of Timeslots in the Time Domain

FIG. 4B illustrates a second block diagram of the noise analyzer used inthe communications receiver according to a second exemplary embodimentof the present invention. A noise analyzer 410 spectrally characterizesand/or spectrally modifies the noisy sequence of data 350 in the timedomain to provide the modified sequence of data 354. The noise analyzer410 additionally analyzes the interference and/or distortion impressedonto the noisy sequence of data 350 to provide the filter coefficientselection signal 356. The noise analyzer 410 characterizes a compositionof the interference and/or distortion embedded within the noisy sequenceof data 350 and provides an indication of the respective set of filterweighting coefficients that corresponds with the composition of theinterference and/or distortion as the filter coefficient selectionsignal 356. The noise analyzer 410 may represent an exemplary embodimentof the noise analyzer 308.

The noise analyzer 410 may include the sampling module 402, theinterference and/or distortion characterization module 408, a timedomain spectral characterization module 412, and a modify time domainspectral characterization module 414. The sampling module 402 samplesthe noisy sequence of data 350 to provide the sampled sequence of data450 in a similar manner as discussed above. Specifically, the noisysequence of data 350 may include one or more inactive timeslots, one ormore active timeslots, or any combination of inactive and activetimeslots. However, this example is not limiting those skilled inrelevant art(s) will recognize that the noisy sequence of data 350 mayinclude orthogonal codes, tones, or other signaling dimensions withoutdeparting from the spirit and scope of the invention. The samplingmodule 402 samples one or more of the inactive timeslots and or theactive timeslots that are, in effect, inactive timeslots to provide thesampled sequence of data 450.

The time domain spectral characterization module 412 spectrallycharacterizes the sampled sequence of data 450 in the time domain toprovide a time domain spectral characterization 458. For example, thetime domain spectral characterization module 412 may determine anautocorrelation function of the sampled sequence of data 450 to providean autocorrelation matrix as the time domain spectral characterization458. However, this example is not limiting, the time domain spectralcharacterization module 412 may determine correlation,cross-correlation, or any other suitable time-domain statistical metricthat will be apparent to those skilled in the relevant art(s) withoutdeparting from the spirit and scope of the present invention.

The time domain spectral characterization module 412 additionallyprovides a time domain spectral characterization information signal 460based on the sampled sequence of data 450 to communicate informationregarding the sampled sequence of data 450, the time domain spectralcharacterization 458, and/or any suitable information acquired whiledetermining the time domain spectral characterization 452 that will beapparent to those skilled in the relevant art(s) to the interferenceand/or distortion characterization module 408. The time domain spectralcharacterization information signal 454 may include statistical metricssuch as a complete or a partial autocorrelation matrix, a complete or apartial correlation matrix, and/or a complete or a partialcross-correlation matrix or any other suitable time-domain statisticalparameter that will be apparent to those skilled in the relevant art(s).

The modify time domain spectral characterization module 414 modifies thetime domain spectral characterization 458 in the time domain to providethe modified sequence of data 354. The modify time domain spectralcharacterization module 414 may raise the noise floor, introducespectral characteristics that relate to previously present interferenceand/or distortion, introduce spectral characteristics of expectedinterference and/or distortion that are expected but that have notrecently been present (or at all been present), and other preemptivemodifications that will be apparent to those skilled in the relevantart(s). For example, the modify time domain spectral characterizationmodule 414 may operate on the time domain spectral characterization 458in the time domain by altering coefficients of the autocorrelationmatrix. As another example, the modify time domain spectralcharacterization module 414 may alter diagonal components of theautocorrelation matrix.

The modify time domain spectral characterization module 414 mayadditionally provide a modified time domain spectral characterizationinformation signal 462 based on the time domain spectralcharacterization 458 to communicate information regarding the timedomain spectral characterization 458, the modified sequence of data 354and/or any suitable information acquired while modifying the time domainspectral characterization 458 to the interference and/or distortioncharacterization module 408. The modified time domain spectralcharacterization information signal 462 may include statistical metricssuch as a noise floor power level, spectral characteristics that relateto previously present interference and/or distortion, spectralcharacteristics of expected interference and/or distortion that areexpected but that have not recently been present (or at all beenpresent), and any other suitable time-domain statistical parameter thatwill be apparent to those skilled in the relevant art(s).

The sampling module 402, the time domain spectral characterizationmodule 404, and the modify time domain spectral characterization module414 are further described in U.S. patent application Ser. No.09/878,730, filed Jun. 11, 2001, entitled “System and Method forCanceling Interference in a Communications System,” now U.S. Pat. No.6,798,854, which is incorporated herein by reference in its entirety.

The interference and/or distortion characterization module 408 mayanalyze the interference and/or distortion impressed onto the inactivesignaling timeslots of the noisy sequence of data 350 based upon atleast one of: the interference cancellation filter information signal360, the decoder information signal 362, the time domain spectralcharacterization information signal 460, and/or the modified time domainspectral characterization information signal 462 to provide the filtercoefficient selection signal 356 in a similar manner as discussed above.

Noise Analysis of Orthogonal Codes in the Frequency Domain

FIG. 4C illustrates a third block diagram of the noise analyzer used inthe communications receiver according to a third exemplary embodiment ofthe present invention. A noise analyzer 416 spectrally characterizesand/or spectrally modifies the noisy sequence of data 350 in thefrequency domain and/or the time domain to provide the modified sequenceof data 354. The noise analyzer 416 additionally analyzes theinterference and/or distortion impressed onto the noisy sequence of data350 to provide the filter coefficient selection signal 356. The noiseanalyzer 416 characterizes a composition of the interference and/ordistortion embedded within the noisy sequence of data 350 and providesan indication of the respective set of filter weighting coefficientsthat corresponds with the composition of the interference and/ordistortion as the filter coefficient selection signal 356. The noiseanalyzer 416 may represent an exemplary embodiment of the noise analyzer308.

The noise analyzer 416 may include the sampling module 402, theinterference and/or distortion characterization module 408, a frequencydomain spectral characterization module 418, a modify frequency domainspectral characterization module 420, and a time domain spectralcharacterization module 422. The sampling module 402 samples the noisysequence of data 350 to provide the sampled sequence of data 450 in asimilar manner as discussed above. Specifically, the noisy sequence ofdata 350 may include one or more inactive orthogonal codes, one or moreactive orthogonal codes, or any combination of inactive and activeorthogonal codes. However, this example is not limiting those skilled inrelevant art(s) will recognize that the noisy sequence of data 350 mayinclude timeslots tones, or other signaling dimensions without departingfrom the spirit and scope of the invention. The sampling module 402samples one or more of the inactive orthogonal codes and or the activeorthogonal codes that are, in effect, inactive orthogonal codes toprovide the sampled sequence of data 450.

The frequency domain spectral characterization module 418 spectrallycharacterizes the sampled sequence of data 450 in the frequency domainto provide a frequency domain spectral characterization 464. Thefrequency domain spectral characterization module 418 transforms thesampled sequence of data 450 from the time domain to the frequencydomain. For example, the frequency domain spectral characterizationmodule 418 may perform a Fast Fourier Transform (FFT) upon the sampledsequence of data 450 to provide the frequency domain spectralcharacterization 464. In this example, the frequency domain spectralcharacterization 464 will include one or more frequency bins within afrequency band of interest. Each frequency bin corresponds to a uniquefrequency in the frequency band of interest and may include a magnitudecomponent and/or an angular component. Alternatively, the frequencydomain spectral characterization module 418 may spectrally characterizethe sampled sequence of data 450 in the time domain followed bytransforming the sampled sequence of data 450 from the time domain tothe frequency domain. In another alternative, the frequency domainspectral characterization module 418 may transform the sampled sequenceof data 450 from the time domain to the frequency domain followed byspectrally characterizing the sampled sequence of data 450 in thefrequency domain.

The frequency domain spectral characterization module 418 additionallyprovides a frequency domain spectral characterization information signal466 based on the sampled sequence of data 450 to communicate informationregarding the sampled sequence of data 450, the frequency domainspectral characterization 464, and/or any suitable information acquiredwhile determining the frequency domain spectral characterization 464 tothe interference and/or distortion characterization module 408. Thefrequency domain spectral characterization information signal 466 mayinclude statistical metrics relating to some or all of the frequencybins of the frequency domain spectral characterization 464.

The modify frequency domain spectral characterization module 420modifies the frequency domain spectral characterization 464 in thefrequency domain to provide a modified frequency domain spectralcharacterization 468. The modify frequency domain spectralcharacterization module 420 may raise the noise floor, introducespectral characteristics that relate to previously present interferenceand/or distortion, introduce spectral characteristics of expectedinterference and/or distortion that are expected but that have notrecently been present (or at all been present), and other preemptivemodifications that will be apparent to those skilled in the relevantart(s).

The modify frequency domain spectral characterization module 420additionally provides a modified frequency domain spectralcharacterization information signal 470 based on the frequency domainspectral characterization 464 to communicate information regarding thefrequency domain spectral characterization 464, the modified frequencydomain spectral characterization 468 and/or any suitable informationacquired while modifying the frequency domain spectral characterization464 to the interference and/or distortion characterization module 408.The modified frequency domain spectral characterization informationsignal 470 may include statistical metrics such as a noise floor powerlevel, spectral characteristics that relate to previously presentinterference and/or distortion, spectral characteristics of expectedinterference and/or distortion that are expected but that have notrecently been present (or at all been present), and any other suitablefrequency domain statistical parameter that will be apparent to thoseskilled in the relevant art(s).

The time domain spectral characterization module 422 characterizes themodified frequency domain spectral characterization 468 in the timedomain to provide the modified sequence of data 354. The time domainspectral characterization module 422 transforms the modified frequencydomain spectral characterization 468 from the frequency domain to thetime domain. For example, the time domain spectral characterizationmodule 422 may perform an Inverse Fast Fourier Transform (IFFT) upon themodified frequency domain spectral characterization 468 to provide themodified sequence of data 354. The time domain spectral characterizationmodule 422 then spectrally characterizes the modified frequency domainspectral characterization 468 in the time domain to provide the modifiedsequence of data 354. For example, the time domain spectralcharacterization module 422 may determine an autocorrelation function ofthe modified frequency domain spectral characterization 468 to providean autocorrelation matrix as the modified sequence of data 354. However,this example is not limiting, the time domain spectral characterizationmodule 422 may determine correlation, cross-correlation, or any othersuitable time-domain statistical metric that will be apparent to thoseskilled in the relevant art(s) without departing from the spirit andscope of the present invention.

The time domain spectral characterization module 422 additionallyprovides a time domain spectral characterization information signal 472based on the modified frequency domain spectral characterization 468 tocommunicate information regarding the frequency domain spectralcharacterization 464, the modified frequency domain spectralcharacterization 468 and/or any suitable information acquired whilecharacterizing the modified frequency domain spectral characterization468 to the interference and/or distortion characterization module 408.The time domain spectral characterization information signal 472 mayinclude statistical metrics such as a complete or a partialautocorrelation matrix, a complete or a partial correlation matrix,and/or a complete or a partial cross-correlation matrix or any othersuitable time-domain statistical parameter that will be apparent tothose skilled in the relevant art(s).

The frequency domain spectral characterization module 418, the modifyfrequency domain spectral characterization module 420, and the timedomain spectral characterization module 422 are further described inU.S. patent application Ser. No. 09/878,730, filed Jun. 11, 2001,entitled “System and Method for Canceling Interference in aCommunications System,” now U.S. Pat. No. 6,798,854, which isincorporated herein by reference in its entirety.

The interference and/or distortion characterization module 408 mayanalyze the interference and/or distortion impressed onto the noisysequence of data 350 based upon at least one of: the interferencecancellation filter information signal 360, the decoder informationsignal 362, the frequency domain spectral characterization informationsignal 466, and/or the modified frequency domain spectralcharacterization information signal 470 to provide the filtercoefficient selection signal 356 in a similar manner as discussed above.

Coefficient Generator of the First Exemplary Communications Receiver

FIG. 5A illustrates a first block diagram of a coefficient generatorused in the communications receiver according to a first exemplaryembodiment of the present invention. The coefficient generator 500includes one or more sets of filter weighting coefficients for use bythe interference cancellation filter 304. The coefficient generator 500determines which set of filter weighting coefficients corresponds withthe composition of the interference and/or distortion based upon one ormore of the filter coefficient selection signal 356, interferencecancellation filter information signal 360, and/or the decoderinformation signal 362. The coefficient generator may provide arespective set of filter weighting coefficients from the one or moresets of filter weighting coefficients that corresponds with thecomposition of the interference and/or distortion as the filterweighting coefficients 358. The coefficient generator 500 may representan exemplary embodiment of the coefficient generator 310.

The coefficient generator 500 includes L filter coefficient updaters502.1 through 502.L. Each of the filter coefficient updaters 502.1through 502.L includes a corresponding set of filter coefficients fromone or more sets of filter weighting coefficients. The corresponding setof the filter coefficients may be used to compensate for theinterference and/or distortion impressed upon the transmittedcommunications signal 152 in the presence of corresponding time-varyingconditions from among the one or more time-varying conditions. Forexample, the filter coefficients to compensate for the absence of thefirst time-varying condition and the second time-varying condition maybe included within the filter coefficient updater 502.1. The noiseanalyzer 308 provides the filter coefficient selection signal 356indicative of the absence of the first time-varying condition and thesecond time-varying condition. In response to the filter coefficientselection signal 356, the filter coefficient updater 502.1 provides thefilter coefficients stored in the filter coefficient updater 502.1 asthe filter weighting coefficients 358.

Likewise, the filter coefficients to compensate for the firsttime-varying condition may included within the filter coefficientupdater 502.2. The noise analyzer 308 provides the filter coefficientselection signal 356 indicative of the presence of the firsttime-varying condition. In response to the filter coefficient selectionsignal 356, the filter coefficient updater 502.2 provides the filtercoefficients stored in the filter coefficient updater 502.2 as thefilter weighting coefficients 358.

Similarly, the filter coefficients to compensate for the secondtime-varying condition may included within the filter coefficientupdater 502.3. The noise analyzer 308 provides the filter coefficientselection signal 356 indicative of the presence of the secondtime-varying condition. In response to the filter coefficient selectionsignal 356, the filter coefficient updater 502.3 provides the filtercoefficients stored in the filter coefficient updater 502.3 as thefilter weighting coefficients 358.

Likewise, the filter coefficients to compensate for the firsttime-varying condition and the second time-varying condition mayincluded within the filter coefficient updater 502.4. The noise analyzer308 provides the filter coefficient selection signal 356 indicative ofthe presence of the first time-varying condition and the secondtime-varying condition. In response to the filter coefficient selectionsignal 356, the filter coefficient updater 502.3 provides the filtercoefficients stored in the filter coefficient updater 502.3 as thefilter weighting coefficients 358.

The filter coefficient updaters 502.1 through 502.L may additionallytrain or adapt their corresponding filter coefficients based upon one ormore of the filter coefficient selection signal 356, interferencecancellation filter information signal 360, and/or the decoderinformation signal 362. For example, when the filter coefficientselection signal 356 indicates the composition of the interferenceand/or distortion condition corresponds to the filter coefficientsincluded within the filter coefficient updater 502.1, the filtercoefficient updater 502.1 adapts its respective filter coefficients. Thefilter coefficients included within the remainder of the filtercoefficient updaters 502 continue in their current state until selectedby the filter coefficient selection signal 356. The filter coefficientupdaters 502.1 through 502.L may use one or more of the modifiedsequence of data 354, the interference cancellation filter informationsignal 360, and the decoder information signal 362 to update theirrespective filter coefficients through a weight computation algorithm asdescribed in U.S. patent application Ser. No. 09/878,730, filed Jun. 11,2001, entitled “System and Method for Canceling Interference in aCommunications System,” now U.S. Pat. No. 6,798,854, which isincorporated herein by reference in its entirety.

FIG. 5B illustrates a second block diagram of the coefficient generatorused in the communications receiver according to a second exemplaryembodiment of the present invention. The coefficient generator 504includes one or more sets of filter weighting coefficients for use bythe interference cancellation filter 304. The coefficient generator 504determines which set of filter weighting coefficients corresponds withthe composition of the interference and/or distortion based upon one ormore of the filter coefficient selection signal 356, interferencecancellation filter information signal 360, and/or the decoderinformation signal 362. The coefficient generator may provide arespective set of filter weighting coefficients from the one or moresets of filter weighting coefficients that corresponds with thecomposition of the interference and/or distortion as the filterweighting coefficients 358. The coefficient generator 504 may representan exemplary embodiment of the coefficient generator 310.

The coefficient generator 504 includes filter coefficient banks 506.1through 506.L, a filter coefficient selector 510, and a filtercoefficient updater 508. The filter coefficient banks 506.1 through506.L provide filter coefficients 552.1 through 552.L based upon updatedfilter coefficients 550.1 through 550.L. More specifically, each one ofthe filter coefficient banks 506.1 through 506.L receives a respectiveone of the one or more sets of filter weighting coefficients via acorresponding updated filter coefficient 550.1 through 550.L. Each oneof the filter coefficient banks 506.1 through 506.L then provides therespective one of the one or more sets of filter weighting coefficientsto a corresponding filter coefficient 552.1 through 552.L.

The corresponding set of the filter coefficients may be used tocompensate for the interference and/or distortion impressed upon thetransmitted communications signal 152 in the presence of a correspondingof time-varying conditions from among the one or more time-varyingconditions. For example, the filter coefficients to compensate for:

1. the absence of the first time-varying condition and the secondtime-varying condition may be included within the filter coefficientbank 506.1;

2. the first time-varying condition may be included within the filtercoefficient bank 506.2;

3. the second time-varying condition may be included within the filtercoefficient bank 506.3; and/or

4. the first time-varying condition and the second time-varyingcondition may be included within the filter coefficient bank 506.4.

However, these examples are not limiting, those skilled in the relevantart(s) will recognize that the filter coefficients used to compensatefor more or less time-varying conditions may be included within thefilter coefficient banks 506.1 through 506.L in accordance with theteachings herein without departing from the spirit and scope of thepresent invention.

The filter coefficient updater 508 may train or adapt one or more setsof filter weighting coefficients. The filter coefficient updater 508 mayprovide the updated filter coefficients 550.1 through 550.L to thefilter coefficient banks 506.1 through 506.L. For example, when the oneor more of the filter coefficient selection signal 356, interferencecancellation filter information signal 360, and/or the decoderinformation signal 362 indicates the composition of the interferenceand/or distortion condition corresponds to the filter coefficientsincluded within the filter coefficient bank 506.1, the filtercoefficient updater 508 selects the filter coefficient 552.1corresponding to the filter coefficient bank 506.1. The filtercoefficient updater 508 then adapts the filter coefficient 552.1. Thefilter coefficients 552.2 through 552.L continue in their current stateuntil selected by the filter coefficient selection signal 356. Thefilter coefficient updater 508 then provides the updated filtercoefficient 550.1 to the filter coefficient bank 506. The filtercoefficient updater 508 may use one or more of the modified sequence ofdata 354, the interference cancellation filter information signal 360,and the decoder information signal 362 to update the filter coefficients552.1 through 552.L through a weight computation algorithm as describedin U.S. patent application Ser. No. 09/878,730, filed Jun. 11, 2001,entitled “System and Method for Canceling Interference in aCommunications System,” now U.S. Pat. No. 6,798,854, which isincorporated herein by reference in its entirety.

The filter coefficient selector 510 selects a corresponding one of thefilter coefficients 552.1 through 552.L based on the filter coefficientselection signal 356 to provide the filter weighting coefficients 358.For example, when the filter coefficient selection signal 356 indicatesthe composition of the interference and/or distortion conditioncorresponds to the filter coefficients provided by the filtercoefficient bank 506.1, the filter coefficient selector 510 may selectthe filter coefficient 552.1 as the filter weighting coefficients 358.

First Exemplary Embodiment of the Interference Cancellation Filter

From the discussion above, the transmitted communications signal 152 mayinclude active signaling dimensions, such as active timeslots to providean example, inactive signaling dimensions, such as inactive timeslots toprovide an example, or any combination of active and inactive signalingdimensions. The interference cancellation filter 304 compensates for theinterference and/or distortion in the presence of the one or moretime-varying conditions embedded in the active time slots of the noisysequence of data 350 by analyzing the interference and/or distortion inthe presence of the one or more time-varying conditions within theinactive time slots or those active time slots that are, in effect,inactive time slots.

FIG. 6 illustrates a first block diagram of an interference cancellationfilter used in the communications receiver according to a firstexemplary embodiment of the present invention. An interferencecancellation filter 600 compensates for the interference and/ordistortion in the presence of the one or more time-varying conditionsembedded in the noisy sequence of data 350 to provide the noisecompensated sequence of data 352. The interference cancellation filter600 may represent an exemplary embodiment of the interferencecancellation filter 304.

The interference cancellation filter 600 includes a delay module 602, afinite impulse response (FIR) filter 604, a summation module 606, anadaptive equalizer 608, a summation module 610, a decision feedbackequalizer (DFE) 612, and a decision device 614. The delay module 602delays the noisy sequence of data 350 by one or more samples to providea delayed noisy sequence of data 650. In an exemplary embodiment, thedelay module 602 delays the noisy sequence of data 350 by a unit delayof one sample.

The finite impulse response (FIR) filter 604 provides a filteredsequence of data 652 based upon the delayed noisy sequence of data 650.The FIR filter 604 adaptively adjusts an impulse response based upon thefilter weighting coefficients 358 to compensate for the interferenceand/or distortion embedded in the delayed noisy sequence of data 650 inthe presence of the one or more time-varying conditions. Morespecifically, the FIR filter 604 is implemented using one or more taps,each tap including one or more delays coupled to a correspondingmultiplier from a plurality of multipliers. The filter weightingcoefficients 358 are used to assign weights to the one or more taps ofthe FIR filter 604 to adjust the impulse response. The summation module606 combines the noisy sequence of data 350 and the filtered sequence ofdata 652 to provide an attenuated sequence of data 654.

The adaptive equalizer 608 further attenuates the interference and/ordistortion in the presence of the one or more time-varying conditions toprovide a feed forward equalized sequence of data 656. The adaptiveequalizer 608 adaptively adjusts an impulse response according tointernal equalization coefficients. The internal equalizationcoefficients for the adaptive equalizer 608 are updated with aleast-squares algorithm, such as the widely known Least Mean Squared(LMS), Recursive Least Squares (RLS), Minimum Mean Squared Error (MMSE)algorithms or any suitable equivalent algorithm that yields aleast-squares result. In other words, the least-squares algorithm or thesuitable equivalent may train the adaptive equalizer 608 to allow theadaptive equalizer 608 to further attenuate the interference and/ordistortion within the attenuated sequence of data 654 in the presence ofthe one or more time-varying conditions. The adaptive equalizer 608 maybe implemented as, but is not limited to, a decision feedback equalizer(DFE), a feed forward equalizer (FFE), any suitable interferencecancellation circuit, a concatenation of an interference cancellationcircuit and/or adaptive equalizer, and/or any combination thereof. In anexemplary embodiment, the adaptive equalizer 608 is optional. In thisembodiment, the summation module 606 may directly provide the attenuatedsequence of data 654 to the summation module 610.

The summation module 610 combines the feed forward equalized sequence ofdata 656 and a decision feedback equalized sequence of data 658 toprovide an equalized sequence of data 660. The decision feedbackequalizer (DFE) 612 provides the decision feedback equalized sequence ofdata 658 based upon the noise compensated sequence of data 352. The DFE612 adaptively adjusts an impulse response based upon the filterweighting coefficients 358 to further compensate for the interferenceand/or distortion embedded in the noise compensated sequence of data 352in the presence of the one or more time-varying conditions. The filterweighting coefficients 358 may be used to adjust the impulse response byassigning weights to one or more taps of the DFE 612.

The decision device 614 determines the most-likely transmitted sequenceof modulation symbols of the transmitted communications signal 152,commonly referred to as decisions, based on the equalized sequence ofdata 660 to provide the noise compensated sequence of data 352. Thenoise compensated sequence of data 352 may include a hard decision or asoft decision. The decision device 614 compares the equalized sequenceof data 660 to a threshold and assigns a digital value based on thecomparison to provide the hard decision. Alternatively, the decisiondevice 614 may incorporate other information, such as a slicer error, abit error ratio (BER) estimate, a symbol error ratio (SER) estimate, asignal to noise ratio (SNR) or any other suitable signal parameter intothe hard decision to provide the soft decision. The decision device 614provides the interference cancellation filter information signal 360based on the equalized sequence of data 660. The interferencecancellation filter information signal 360 may include signal parameterssuch as a slicer error, a bit error rate (BER), a symbol error rate(SER), a signal to noise ratio (SNR) or any other suitable signalparameter that will be apparent to those skilled in the relevant art(s).

This embodiment of the interference cancellation filter 600 is furtherdescribed in U.S. patent application Ser. No. 09/878,730, filed Jun. 11,2001, entitled “System and Method for Canceling Interference in aCommunications System,” now U.S. Pat. No. 6,798,854, which isincorporated herein by reference in its entirety.

Despreading of Signaling Dimensions

Alternatively, the transmitted communications signal 152 may includeactive signaling dimensions, inactive signaling dimensions, or anycombination of active and inactive signaling dimensions. Theinterference cancellation filter 304 compensates for the interferenceand/or distortion in the presence of the one or more time-varyingconditions embedded in the active signaling dimensions of the noisysequence of data 350 by analyzing the interference and/or distortion inthe presence of the one or more time-varying conditions within theinactive signaling dimensions or those active signaling dimensions thatare, in effect, inactive signaling dimensions.

The compensation of the interference and/or distortion in the presenceof the one or more time-varying conditions embedded in the activesignaling dimensions, such as the active orthogonal codes to provide anexample, includes matched filtering of the inactive signaling dimensionsand/or active signaling dimensions of the noisy sequence of data 350.This matched filtering of the inactive signaling dimensions and/oractive signaling dimensions is referred to as vector despreading orsimply despreading. Vector despreading represents a process ofseparating a combined communication signal having the inactive signalingdimensions and/or the active signaling dimensions into separatecommunications signals, each of the separate communications signalsrepresentative of one of the inactive signaling dimensions and/or theactive signaling dimensions.

FIG. 7A illustrates a first block diagram of a vector despreading moduleused in the interference cancellation filter according to a firstexemplary embodiment of the present invention. A vector despreader 702decomposes or separates the one or more signaling dimensions of thenoisy sequence of data 350 into signaling dimensions, or components,750.1 through 750.N. More specifically, the noisy sequence of data 350represents a combined sequence of data including at least one signalingdimension, such as at least one of the inactive signaling dimensionsand/or the active signaling dimensions. The vector despreader 702separates or decomposes each of the combined signaling dimensions of thenoisy sequence of data 350 into its respective signaling dimension, orcomponent, 750.1 through 750.N.

The vector despreader 702 includes matched filter modules 704.1 through704.N. The matched filter modules 704.1 through 704.N filter at leastone signaling dimension from the noisy sequence of data 350 using acorresponding transfer function H₁(f) through H_(N)(f) to provide acorresponding one of the signaling dimensions, or components, 750.1through 750.N. The transfer functions H₁(f) through H_(N)(f) effectivelyseparate or isolate the at least one signaling dimension, or component,from within the combined signaling dimensions 750.1 through 750.N.

Despreading of Orthogonal Codes

As an example, the transmitted communications signal 152 may includeactive orthogonal spreading codes, inactive orthogonal spreading codes,or any combination of active and inactive orthogonal spreading codes.Orthogonal spreading codes may also be referred to as orthogonal codes.The interference cancellation filter 304 compensates for theinterference and/or distortion in the presence of the one or moretime-varying conditions embedded in the active orthogonal codes of thenoisy sequence of data 350 by analyzing the interference and/ordistortion in the presence of the one or more time-varying conditionswithin the inactive orthogonal codes or those active orthogonal codesthat are, in effect, inactive orthogonal codes. The compensation of theinterference and/or distortion in the presence of the one or moretime-varying conditions embedded in the active orthogonal codes requiresdecomposition of noisy sequence of data 350 into its distinct inactiveorthogonal codes and/or active orthogonal codes.

FIG. 7B illustrates a second block diagram of a vector despreadingmodule used in the interference cancellation filter according to asecond exemplary embodiment of the present invention. A vectordespreader 708 decomposes or separates the one or more orthogonal codescomprising the noisy sequence of data 350 into the orthogonal codecomponents 756.1 through 756.N. More specifically, the noisy sequence ofdata 350 represents a combined sequence of data including at least oneorthogonal code, such as at least one of the inactive orthogonal codesand/or the active orthogonal codes. The vector despreader 708 separatesor isolates each of the orthogonal codes of the noisy sequence of data350 into its respective orthogonal code, or component or dimension,756.1 through 756.N. While the operation of despreading produces arelative value (or component value) corresponding to each spreading codecomprising the composite signal, hereafter the produced component valuemay be referred to with shortened nomenclature as the “signalingdimension”, or “spreading code”, or “orthogonal code” itself, instead ofreferring to the despread value in its literal sense as the relative(signed) size or value of the dimension or code which was generated orisolated by the despreading, and which is the actual component. In otherwords, the operation of despreading generates a set of componentscorresponding to the constituent dimensions, but this will be referredto as despreading and producing the dimensions themselves.

The vector despreader 708 includes multipliers 704.1 through 704.N andsummation modules 710.1 through 710.N. The multipliers 704.1 through704.N multiply the noisy sequence of data 350 by despreading signalingsequences C₁ through C_(N) to wipeoff the spreading. The summationmodules 708.1 through 708.N combine the N chips of each of theorthogonal codes 754.1 through 754.N to provide the matched filtered,decomposed or isolated or separated orthogonal code components 756.1through 756.N.

Second Exemplary Embodiment of the Interference Cancellation Filter

FIG. 8A illustrates a second block diagram of the interferencecancellation filter used in the communications receiver according to asecond exemplary embodiment of the present invention. An interferencecancellation filter 800 may compensate for the interference and/ordistortion in the presence of the one or more time-varying conditionsembedded in the noisy sequence of data 350 to provide the noisecompensated sequence of data 352. The interference cancellation filter800 may represent an exemplary embodiment of the interferencecancellation filter 304.

The interference cancellation filter 800 includes a vector despreader802, a linear combination module 804, and the decision device 614. Thevector despreader 802 separates or decomposes the noisy sequence of data350 into signaling dimension components 852.1 through 852.N. From thediscussion above, the noisy sequence of data 350 includes at least onesignaling dimension of which may include the inactive signalingdimensions and/or the active signaling dimensions. The vector despreader802 separates each of the signaling dimensions of the noisy sequence ofdata 350 into a corresponding one of the signaling dimensions 852.1through 852.N. The signaling dimensions 852.1 through 852.i mayrepresent the inactive signaling dimensions, whereas the signalingdimensions 852.(i+1) through 852.N represent the inactive signalingdimensions.

The vector despreader 802 may represent an exemplary embodiment of thevector despreader 702 as discussed in FIG. 7A or the vector despreader708 as discuss in FIG. 7B. As such, the signaling dimension components852.1 through 852.N may represent either the signaling dimensions 750.1through 750.N as discussed in FIG. 7A or the orthogonal codes 756.1through 756.N as discussed in FIG. 7B.

The linear combination module 804 may compensate for the interferenceand/or distortion in the presence and/or absence of the one or moretime-varying conditions in one of the signaling dimensions 852.1 through852.N, denoted as the signaling dimension 852.s in FIG. 8A. Thesignaling dimension 852.s may correspond to one of the active signalingdimensions of the noisy sequence of data 350. Alternatively, thesignaling dimension 852.s may correspond to one of the inactivesignaling dimensions of the noisy sequence of data 350. As shown in FIG.8A, the linear combination module 804 includes scaling modules 810.1through 810.i and a summation module 812. The scaling modules 810.1through 810.i scale the signaling dimensions 852.1 through 852.i,corresponding to the inactive signaling dimensions, by weightingcoefficients w₁ through w_(i) to provide weighted signaling dimensions854.1 through 854.i. The weighting coefficients w₁ through w_(i) may beprovided to the linear combination module 804 by the coefficientgenerator 310 via the filter weighting coefficients 358 in a similarmanner as discussed above. The summation module 812 combines theweighted signaling dimensions 854.1 through 854.i and the signalingdimension 852.s to provide the signaling dimension 856. The signalingdimension 856 includes the signaling dimension 852.s having a reductionin interference and/or distortion in the presence of the one or moretime-varying conditions.

The decision device 614 provides decisions and/or the interferencecancellation filter information signal 360 based on the signalingdimension 856 to provide the noise compensated sequence of data 352 in asimilar manner as discussed above.

The interference cancellation filter 800 is further described in U.S.patent application Ser. No. 10/142,189, filed May 8, 2002, entitled“Cancellation of Interference in a Communication System with Applicationto S-CDMA,” now U.S. Pat. No. 7,110,434, which is incorporated herein byreference in its entirety.

FIG. 8B illustrates a third block diagram of the interferencecancellation filter used in the communications receiver according to athird exemplary embodiment of the present invention. An interferencecancellation filter 820 may compensate for the interference and/ordistortion in the presence of the one or more time-varying conditionsembedded in the noisy sequence of data 350 to provide the noisecompensated sequence of data 352. The interference cancellation filter820 may represent an exemplary embodiment of the interferencecancellation filter 304.

The interference cancellation filter 820 includes the vector despreader802 and a linear combination module 822. The vector despreader 802separates the noisy sequence of data 350 into signaling dimensions 852.1through 852.N in a substantially similar manner as discussed above. Thesignaling dimensions 852.1 through 852.i may represent the inactivesignaling dimensions, whereas the signaling dimensions 852.(i+1) through852.N represent the inactive signaling dimensions.

The linear combination module 822 may compensate for the interferenceand/or distortion in the presence and/or absence of the one or moretime-varying conditions in one of the signaling dimensions 852.1 through852.N, denoted as the signaling dimension 852.s in FIG. 8B. Thesignaling dimension 852.s may correspond to one of the active signalingdimensions of the noisy sequence of data 350. Alternatively, thesignaling dimension 852.s may correspond to one of the inactivesignaling dimensions of the noisy sequence of data 350. As shown in FIG.8B, the linear combination module 822 includes the scaling modules 810.1through 810.i, scaling modules 824.s through 824.N, and a summationmodule 826. The scaling modules 810.1 through 810.i scale the signalingdimensions 852.1 through 852.i, corresponding to the inactive signalingdimensions, by weighting coefficients w₁ through w_(i) to provideweighted signaling dimensions 854.1 through 854.i in a similar manner asdiscussed above. The scaling modules 824.1 through 824.i scale thesignaling dimensions 852.(i+1) through 852.N, corresponding to theactive signaling dimensions, by weighting coefficients w_(i+)1) throughw_(N) to provide weighted signaling dimensions 854.(i+1) through 854.N.The weighting coefficients w_((i+)1) through W_(N) may be provided tothe linear combination module 822 by the coefficient generator 310 viathe filter weighting coefficients 358 in a similar manner as discussedabove.

The summation module 812 combines the weighted signaling dimensioncomponents 854.1 through 854.N to provide one of the signalingdimensions combined in the noisy sequence of data 350 as the signalingdimension 856. The decision device 614 provides decisions and/or theinterference cancellation filter information signal 360 based on thesignaling dimension component 856 to provide the noise compensatedsequence of data 352 in a similar manner as discussed above.

The interference cancellation filter 820 is further described in U.S.patent application Ser. No. 10/142,189, filed May 8, 2002, entitled“Cancellation of Interference in a Communication System with Applicationto S-CDMA,” now U.S. Pat. No. 7,110,434, which is incorporated herein byreference in its entirety.

FIG. 8C illustrates a fourth block diagram of the interferencecancellation filter used in the communications receiver according to afourth exemplary embodiment of the present invention. An interferencecancellation filter 840 may compensate for the interference and/ordistortion in the presence of the one or more time-varying conditionsembedded in the noisy sequence of data 350 to provide the noisecompensated sequence of data 352.

The interference cancellation filter 840 may represent an exemplaryembodiment of the interference cancellation filter 304.

The interference cancellation filter 840 includes the vector despreader802 and a linear combination module 822. The vector despreader 802separates the noisy sequence of data 350 into signaling dimensions 852.1through 852.N in a substantially similar manner as discussed above. Thesignaling dimensions 852.1 through 852.i may represent the inactivesignaling dimensions, whereas the signaling dimensions 852.(i+1) through852.N represent the inactive signaling dimensions.

The linear combination module 842 may compensate for the interferenceand/or distortion in the presence and/or absence of the one or moretime-varying conditions in one of the signaling dimensions 852.1 through852.N, denoted as the signaling dimension 852.s in FIG. 8C. Thesignaling dimension 852.s may correspond to one of the active signalingdimensions of the noisy sequence of data 350. Alternatively, thesignaling dimension 852.s may correspond to one of the inactivesignaling dimensions of the noisy sequence of data 350.

As shown in FIG. 8C, the linear combination module 842 includes adaptiveequalizers 844.1 through 844.i and the summation module 812. Each of theadaptive equalizers 844.1 through 844.i adaptively adjusts itsrespective impulse response according to one or more sets ofequalization coefficients to provide weighted signaling dimensions 854.1through 854.i. The one or more sets of equalization coefficients may beprovided to the linear combination module 842 by the coefficientgenerator 310 via the filter weighting coefficients 358 in a similarmanner as discussed above. Each of the adaptive equalizers 844.1 through844.i may be implemented as, but is not limited to, a decision feedbackequalizer (DFE), a feed forward equalizer (FFE), any suitableinterference cancellation circuit, a concatenation of an interferencecancellation circuit and/or adaptive equalizer, and/or any combinationthereof.

The summation module 812 combines the weighted signaling dimensions854.1 through 854.i to provide the despread code 856.

The decision device 614 provides the noise compensated sequence of data352 and/or the interference cancellation filter information signal 360based on the signaling dimension 856 in a similar manner as discussedabove.

The interference cancellation filter 840 is further described in U.S.patent application Ser. No. 10/142,189, filed May 8, 2002, entitled“Cancellation of Interference in a Communication System with Applicationto S-CDMA,” now U.S. Pat. No. 7,110,434, which is incorporated herein byreference in its entirety.

Although not shown in FIG. 8A through FIG. 8C, a substantially similarlinear combiner structure may be applied to the other active and/orinactive signaling dimensions as well. In each case, the desired code isapplied to the respective linear combination module to compensate forthe interference and/or distortion in the presence and/or absence of theone or more time-varying conditions from that code. For each activecode, the same i inactive signaling dimensions are summed with thedesired code, but for each active code the weighting coefficients w₁through w_(i) are in general unique. Likewise, for each inactive code,the same (i−1) inactive signaling dimensions are summed with the desiredcode, but for each active code the weighting coefficients w₁ throughw_((i−1)) are in general unique.

Second Exemplary Communications Receiver

FIG. 9 illustrates a second block diagram of the communications receiverused in the communications environment according to a second exemplaryembodiment of the present invention. A communications receiver 300observes the received communications signal 154 as it passes through thecommunications channel 104. The communications receiver 900 mayrepresent an exemplary embodiment of the communications receiver 106.The communications receiver 900 operates in a substantially similarmanner as the communications receiver 300, thus only differences betweenthe communications receiver 900 and the communications receiver 300 areto be described in further detail.

The interference cancellation filters 902.1 through 902.M compensate forthe interference and/or distortion in the presence of the one or moretime-varying conditions embedded in the active signaling dimensions ofthe noisy sequence of data 350 to provide noise compensated sequences ofdata 950.1 through 950.M. More specifically, the interferencecancellation filters 902.1 through 902.M compensate for the interferenceand/or distortion in:

1. the absence of the first time-varying condition and the secondtime-varying condition using a first one of the interferencecancellation filters 902.1 through 902.M;

2. the presence of the first time-varying condition using a second oneof the interference cancellation filters 902.1 through 902.M;

3. the presence of the second time-varying condition using a third oneof the interference cancellation filters 902.1 through 902.M; and/or

4. the presence of the first time-varying condition and the secondtime-varying condition using a fourth one of the interferencecancellation filters 902.1 through 902.M.

However, these examples are not limiting, those skilled in the relevantart(s) will recognize that the interference cancellation filters 902.1through 902.M may compensate for the interference and/or distortion inthe presence and/or absence of other time-varying conditions inaccordance with the teachings herein without departing from the spiritand scope of the present invention.

The interference cancellation filters 902.1 through 902.M thenadaptively adjusts its corresponding impulse response based upon one ormore sets of filter weighting coefficients to compensate for theinterference and/or distortion embedded in the active signalingdimension of the noisy sequence of data 350 in the presence of the oneor more time-varying conditions.

The interference cancellation filters 902.1 through 902.M additionallyprovide interference cancellation filter information signals 952.1through 952.M based on the active signaling dimension of the noisysequence of data 350 to the to the noise analyzer 904. The interferencecancellation filter information signals 952.1 through 952.M may includesignal parameters such as an average power within a bandwidth of thetransmitted communications signal 152 over a time interval, a slicererror, a bit error rate (BER), a symbol error rate (SER), a signal tonoise ratio (SNR), code information, state information, symbols or bitswhich are determined to be incorrect or questionable, likely correctedvalues for such symbols or bits, probabilities for suggested correctionsor a multiplicity of possible choices for a correction, likelihoodmetrics related to estimated signal fidelity corresponding to the noisysequence of data 350, channel fidelity information as such as disclosedin U.S. patent application Ser. No. 10/000,415, filed Nov. 2, 2001,entitled “Detection and Mitigation of Temporary Impairments in aCommunications Channel,” now U.S. Pat. No. 7,308,050, which isincorporated herein by reference in its entirety, or any other suitablesignal parameter that will be apparent to those skilled in the relevantart(s).

The noise analyzer 904 analyzes the interference and/or distortionimpressed onto the inactive signaling dimensions of the noisy sequenceof data 350 to provide the interference cancellation filter selectionsignal 954. The noise analyzer 904 characterizes a composition of theinterference and/or distortion embedded within the inactive signalingdimensions of the noisy sequence of data 350 to provide an indication ofone or more of the interference cancellation filters 902.1 through 902.Mthat corresponds with the composition of the interference and/ordistortion as the interference cancellation filter selection signal 954.For example, the noise analyzer 904 may characterize the interferenceand/or distortion embedded within the inactive signaling dimensions ofthe noisy sequence of data 350 as:

1. not including the first time-varying condition and the secondtime-varying condition the noise analyzer 904 provides the filtercoefficient selection signal 356 indicative of the absence of the firsttime-varying condition and the second time-varying condition;

2. including the first time-varying condition, the noise analyzer 904provides the filter coefficient selection signal 356 indicative of thepresence of the first time-varying condition;

3. including the second time-varying condition, the noise analyzer 904provides the filter coefficient selection signal 356 indicative of thepresence of the second time-varying condition; and/or

4. including the first time-varying condition and the secondtime-varying condition, the noise analyzer 904 provides the filtercoefficient selection signal 356 indicative of the presence of the firsttime-varying condition and the second time-varying condition.

However, these examples are not limiting, those skilled in the relevantart(s) will recognize that the noise analyzer 904 may characterize theinterference and/or distortion embedded within the inactive signalingdimensions of the noisy sequence of data 350 as other time-varyingconditions in accordance with the teachings herein without departingfrom the spirit and scope of the present invention.

The interference cancellation filter selector 906 selects at least oneof the noise compensated sequences of data 950.1 through 950.M torepresent the one or more sequences of recovered data 156 based upon theinterference cancellation filter selection signal 954. For example, whenthe interference cancellation filter selection signal 954 indicatesinterference cancellation filter 902.1 is to compensate for theinterference and/or distortion embedded in the noisy sequence of data350, the interference cancellation filter selector 906 selects the noisecompensated sequence of data 950.1 to represent the one or moresequences of recovered data 156.

Interference Cancellation Filter for Signaling Dimensions used in theSecond Exemplary Communications Receiver

FIG. 10A illustrates a first block diagram of the interferencecancellation filter used in the second communications receiver accordingto a first exemplary embodiment of the present invention. Aninterference cancellation filter 1000 compensates for the interferenceand/or distortion in the presence of the one or more time-varyingconditions embedded in the active signaling dimension of the noisysequence of data 350 to provide one of the noise compensated sequencesof data 950.1 through 950.M. The interference cancellation filter 1000then adaptively adjusts its corresponding impulse response based uponone or more sets of filter weighting coefficients to compensate for theinterference and/or distortion embedded in the active signalingdimension of the noisy sequence of data 350 in the presence of the oneor more time-varying conditions. The interference cancellation filter1000 may represent an exemplary embodiment of one of the interferencecancellation filters 902.1 through 902.M.

The interference cancellation filter 1000 includes the sampling module402, the spectral characterization module 404, the modify spectralcharacterization module 406, a filter coefficient updater module 1002,an interference cancellation filter 1004, and a FEC decoder 1006. Thesampling module 402 samples the noisy sequence of data 350 to providethe sampled sequence of data 450 in a similar manner as discussed above.Specifically, the noisy sequence of data 350 may include one or moreinactive signaling dimensions, one or more active signaling dimensions,or any combination of inactive and active signaling dimensions. However,this example is not limiting as those skilled in relevant art(s) willrecognize that the noisy sequence of data 350 may include orthogonalcodes, tones, or other signaling dimensions without departing from thespirit and scope of the invention. The sampling module 402 samples oneor more of the inactive signaling dimensions and or the active signalingdimensions that are, in effect, inactive signaling dimensions to providethe sampled sequence of data 450.

The spectral characterization module 404 spectrally characterizes thesampled sequence of data 450 to provide the spectral characterization452. More specifically, the spectral characterization module 404 mayspectrally characterize the inactive signaling dimensions to provide thespectral characterization 452 and the spectral characterizationinformation signal 454

The modify spectral characterization module 406 modifies the spectralcharacterization 452 to provide the modified sequence of data 354 andthe modified spectral characterization information signal 456 in asubstantially similar manner as discussed above.

The filter coefficient updater module 1002 provides a set of filtercoefficients 1050 to the interference cancellation filter 1004. The setof filter coefficients 1050 may be used to compensate for the presenceof the one or more time-varying conditions embedded in the noisysequence of data 350 in a similar manner as the filter coefficientupdaters 502.1 through 502.N and/or the filter coefficient updater 508as discussed above. The filter coefficient updater module 1002 may useone or more of the modified sequence of data 354, the interferencecancellation filter information signal 360, and the decoder informationsignal 362 to update filter coefficients through the weight computationalgorithm in a similar manner as the filter coefficient updaters 502.1through 502.N and/or the filter coefficient updater 508 as discussedabove.

The interference cancellation filter 1004 may compensate for theinterference and/or distortion in the presence of the one or moretime-varying conditions using the set of filter coefficients 1050embedded in the noisy sequence of data 350 to provide a noisecompensated sequence of data 1064. The interference cancellation filter1004 may provide the interference cancellation filter information signal1066 based the noisy sequence of data 350 in a similar manner to theinterference cancellation filter 304 as discussed above.

The interference cancellation filter 1004 compensates for theinterference and/or distortion in the presence of the one or moretime-varying conditions embedded in the active signaling dimensions ofthe noisy sequence of data 350 to provide a noise compensated sequenceof data 1052 in a substantially similar manner as the interferencecancellation filter 304 as described above. The interferencecancellation filter 1004 then adaptively adjusts an impulse responsebased upon the set of filter coefficients 1050 used to compensate forthe interference and/or distortion embedded in the active signalingdimension of the noisy sequence of data 350 in the presence of the oneor more time-varying conditions. The interference cancellation filter1004 additionally provides the interference cancellation filterinformation signal 360 based on the active signaling dimensions of thenoisy sequence of data 350 to the noise analyzer 904 and/or the filtercoefficient updater module 1002 as described above.

The FEC decoder 1006 corrects for errors in the noise compensatedsequence of data 1052 using any suitable decoding scheme to provide oneof the noise compensated sequences of data 950.1 through 950.M in asimilar manner as the FEC decoder 306 as discussed above. The FECdecoder 306 may provide the decoder information signal 362 based on thenoise compensated sequence of data 1052 in a similar manner as the FECdecoder 306 as discussed above.

It should be noted that the interference cancellation filter informationsignals 952.1 through 952.M, as discussed above, may include one or moreof the time domain spectral characterization information signal 454, themodified spectral characterization information signal 456, theinterference cancellation filter information signal 360, and the decoderinformation signal 362.

Interference Cancellation Filter for Timeslots used in the SecondExemplary Communications Receiver

FIG. 10B illustrates a second block diagram of the interferencecancellation filter used in the second communications receiver accordingto a second exemplary embodiment of the present invention. Aninterference cancellation filter 1010 compensates for the interferenceand/or distortion in the presence of the one or more time-varyingconditions embedded in the active timeslots of the noisy sequence ofdata 350 to provide one of the noise compensated sequences of data 950.1through 950.M. The interference cancellation filter 1010 then adaptivelyadjusts its corresponding impulse response based upon one or more setsof filter weighting coefficients to compensate for the interferenceand/or distortion embedded in the active timeslot of the noisy sequenceof data 350 in the presence of the one or more time-varying conditions.The interference cancellation filter 1010 may represent an exemplaryembodiment of one of the interference cancellation filters 902.1 through902.M.

The interference cancellation filter 1010 includes the sampling module402, the time domain spectral characterization module 412, the modifytime domain spectral characterization module 414, the filter coefficientupdater module 1002, the interference cancellation filter 1004, and theFEC decoder 1006. The sampling module 402 samples the noisy sequence ofdata 350 to provide the sampled sequence of data 450 in a similar manneras discussed above. Specifically, the noisy sequence of data 350 mayinclude one or more inactive timeslots, one or more active timeslots, orany combination of inactive and active timeslots. The sampling module402 samples one or more of the inactive timeslots and or the activetimeslots that are, in effect, inactive timeslots to provide the sampledsequence of data 450.

The time domain spectral characterization module 412 spectrallycharacterizes the sampled sequence of data 450 to provide the timedomain spectral characterization 458. More specifically, the time domainspectral characterization module 412 may spectrally characterize theinactive timeslots to provide the time domain spectral characterization458 and the time domain spectral characterization information signal460.

The modify time domain spectral characterization module 414 modifies thetime domain spectral characterization 458 to provide the modifiedsequence of data 354 and modified time domain spectral characterizationinformation signal 462 in a substantially similar manner as discussedabove.

The filter coefficient updater module 1002 provides a set of filtercoefficients 1050 to the interference cancellation filter 1004 to beused to compensate for the presence of the one or more time-varyingconditions embedded in the noisy sequence of data 350 in a similarmanner as discussed above.

The interference cancellation filter 1004 compensates for theinterference and/or distortion in the presence of the one or moretime-varying conditions using the set of filter coefficients 1050embedded in the noisy sequence of data 350 to provide the noisecompensated sequence of data 1064 and provides the interferencecancellation filter information signal 1066 based the noisy sequence ofdata 350 in a similar manner as discussed above.

The interference cancellation filter 1004 compensates for theinterference and/or distortion in the presence of the one or moretime-varying conditions embedded in the active timeslots of the noisysequence of data 350 to provide a noise compensated sequence of data1052 in a substantially similar manner as described above. Theinterference cancellation filter 1004 then adaptively adjusts itsimpulse response based upon the set of filter coefficients 1050 used tocompensate for the interference and/or distortion embedded in the activetimeslot of the noisy sequence of data 350 in the presence of the one ormore time-varying conditions in a substantially similar manner asdescribed above. The interference cancellation filter 1004 additionallyprovides the interference cancellation filter information signal 360based on the active timeslots of the noisy sequence of data 350 to thenoise analyzer 904 and/or the filter coefficient updater module 1002 ina substantially similar manner as described above.

The FEC decoder 1006 corrects for errors in the noise compensatedsequence of data 1052 using any suitable decoding scheme to provide oneof the noise compensated sequences of data 950.1 through 950.N in asubstantially similar manner as described above. The FEC decoder 306 mayprovide the decoder information signal 362 based on the noisecompensated sequence of data 1052 in a substantially similar manner asdescribed above.

It should be noted that the interference cancellation filter informationsignals 952.1 through 952.M, as discussed above, may include one or moreof the time domain spectral characterization information signal 460, themodified time domain spectral characterization information signal 462,the interference cancellation filter information signal 360, and thedecoder information signal 362.

Interference Cancellation Filter for Orthogonal Codes Used in the SecondExemplary Communications Receiver

FIG. 10C illustrates a third block diagram of the interferencecancellation filter used in the second communications receiver accordingto a third exemplary embodiment of the present invention. Aninterference cancellation filter 1020 compensates for the interferenceand/or distortion in the presence of the one or more time-varyingconditions embedded in the active orthogonal codes of the noisy sequenceof data 350 to provide one of the noise compensated sequences of data950.1 through 950.N. The interference cancellation filter 1020 thenadaptively adjusts its corresponding impulse response based upon one ormore sets of filter weighting coefficients to compensate for theinterference and/or distortion embedded in the active timeslot of thenoisy sequence of data 350 in the presence of the one or moretime-varying conditions. The interference cancellation filter 1020 mayrepresent an exemplary embodiment of one of the interferencecancellation filters 902.1 through 902.N.

The interference cancellation filter 1020 includes the frequency domainspectral characterization module 418, the modify frequency domainspectral characterization module 420, the time domain spectralcharacterization module 422, the filter coefficient updater module 1002,the interference cancellation filter 1004, and the FEC decoder 1006. Thesampling module 402 samples the noisy sequence of data 350 to providethe sampled sequence of data 450 in a similar manner as discussed above.Specifically, the noisy sequence of data 350 may include one or moreinactive timeslots, one or more active timeslots, or any combination ofinactive and active timeslots. The sampling module 402 samples one ormore of the inactive timeslots and or the active timeslots that are, ineffect, inactive timeslots to provide the sampled sequence of data 450.

The frequency domain spectral characterization module 418 spectrallycharacterizes the sampled sequence of data 450 in the frequency domainto provide the frequency domain spectral characterization 464 in asimilar manner as discussed above. The frequency domain spectralcharacterization module 418 additionally provides the frequency domainspectral characterization information signal 466 based on the sampledsequence of data 450 in a similar manner as discussed above.

The modify frequency domain spectral characterization module 420modifies the frequency domain spectral characterization 464 in thefrequency domain to provide the modified frequency domain spectralcharacterization 468 in a similar manner as discussed above. The modifyfrequency domain spectral characterization module 420 additionallyprovides the modified frequency domain spectral characterizationinformation signal 470 in a similar manner as discussed above.

The time domain spectral characterization module 422 characterizes themodified frequency domain spectral characterization 468 in the timedomain to provide the modified sequence of data 354 in a similar manneras discussed above.

The filter coefficient updater module 1008 provides the set of filtercoefficients 1026 to the interference cancellation filter 1010. The setof filter coefficients 1026 may be used to compensate for the presenceof the one or more time-varying conditions embedded in the noisysequence of data 350 in a similar manner as discussed above. The filtercoefficient updater module 1008 may use one or more of the modifiedsequence of data 1078, an interference cancellation filter informationsignal 1066, and a decoder information signal 1068 to update filtercoefficients through the weight computation algorithm in a similarmanner as the filter coefficient updaters 502.1 through 502.N and/or thefilter coefficient updater 508 as discussed above.

It should be noted that the interference cancellation filter informationsignals 952.1 through 952.M, as discussed above, may include one or moreof the frequency domain spectral characterization information signal466, the modified frequency domain spectral characterization informationsignal 470, the interference cancellation filter information signal 360,and the decoder information signal 362.

FIG. 11 is a flowchart of exemplary operational steps of a noiseanalyzer according to an aspect of the present invention. The inventionis not limited to this operational description. Rather, it will beapparent to persons skilled in the relevant art(s) from the teachingsherein that other operational control flows are within the scope andspirit of the present invention. The following discussion describes thesteps in FIG. 11

At step 1102, information for analysis is received by a noise analyzermodule, such as the noise analyzer 308, the interference and/ordistortion characterization module 408, and/or the noise analyzer 904 toprovide some examples. The noise analyzer module may operate in a directanalysis method, an indirect analysis method, and/or a combination ofthe direct analysis method and the indirect analysis method. As analternate to the direct analysis method and/or the indirect analysismethod, a method of analysis such as disclosed in U.S. patentapplication Ser. No. 10/391,555, entitled “System and Method forPeriodic Noise Avoidance in Data Transmission Systems,” filed on May 18,2004, now U.S. Pat. No. 7,050,516, which is incorporated by reference inits entirety, may be used.

At step 1104, the information for analysis from step 1102 is processedby the noise analyzer to compute one or more signal metrics of thecommunications signal. The direct analysis method processes theinformation for analysis in non-real-time. As a result of thenon-real-time processing in the direct analysis method, an interferencecancellation filter, such as the interference cancellation filter 304,and/or the interference cancellation filters 902.1 through 902.N toprovide some examples, may buffer or delay the communications signal byone or more bits to allow for the processing of the information foranalysis. The non-real-time processing allows the noise analyzer toanalyze the compensation for the interference and/or distortion in thepresence of the one or more time-varying conditions embedded in thecommunications signal.

For example, the noise analyzer may hypothesize that the one or moretime-varying conditions are present and/or absent from thecommunications signal. The noise analyzer may monitor parameters of theinterference cancellation filter, such as, but not limited to, filtercoefficients to provide an example, to determine an accuracy of thehypothesis. In contrast, the indirect analysis method processes theinformation for analysis in real-time. In an exemplary embodiment, thenoise analyzer hypothesizes whether the communications signal includes awhite or a flat noise spectrum or a noise spectrum including theinterference and/or distortion in the presence of the one or moretime-varying conditions.

At step 1106, the one or more signal metrics from step 1104 arecataloged by the noise analyzer based upon a hypothesis from step 1108.The noise analyzer stores and/or updates the one or more signal metricsto identify the interference and/or distortion in the presence and/orabsence of the one or more time-varying conditions based upon thehypothesis from step 1108. As an example, if step 1108 hypothesizes theinterference and/or distortion includes a first time-varying conditionand a second time-varying condition, the noise analyzer stores and/orupdates the one or more signal metrics corresponding to firsttime-varying condition. The one or more signal metrics corresponding tothe second time-varying condition continue in their current state.

At step 1108, the one or more signal metrics from step 1104 are comparedwith the one or more signal metrics cataloged in step 1106 to generate ahypothesis relating to the presence and/or absence of the one or moretime-varying conditions embedded in the communications signal. In anexemplary embodiment, the hypothesis includes a particular condition isembedded in the communications signal in the presence of the one or moretime-varying conditions.

At step 1110, a selection signal, such as the filter coefficientselection signal 356 and/or the interference cancellation filterselection signal 854 to provide some examples, is generated based uponthe hypothesis from step 1108.

CONCLUSION

It is to be appreciated that the Detailed Description section, and notthe Abstract section, is intended to be used to interpret the claims.The Abstract section may set forth one or more, but not all exemplaryembodiments, of the present invention, and thus, are not intended tolimit the present invention and the appended claims in any way.

The present invention has been discussed above with the aid offunctional building blocks illustrating the implementation of specifiedfunctions and relationships thereof. The boundaries of these functionalbuilding blocks have been arbitrarily defined herein for the convenienceof the description. Alternate boundaries may be defined so long as thespecified functions and relationships thereof are appropriatelyperformed.

It will be apparent to those skilled in the relevant art(s) that variouschanges in form and detail can be made therein without departing fromthe spirit and scope of the present invention. Thus, the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the followingclaims and their equivalents.

1. A communications receiver configured to compensate for one or moretime-varying conditions embedded onto a sequence of data, comprising: anoise analyzer configured to spectrally modify the sequence of data toprovide a modified sequence of data and to analyze a composition of theone or more time-varying conditions to provide a filter coefficientselection signal; a coefficient generator including a plurality offilter coefficient updaters, each filter coefficient updater having aset of filter coefficients, the coefficient generator being configuredto select a corresponding set of filter coefficients in accordance withthe filter coefficient selection signal; and an interferencecancellation filter configured to compensate for the one or moretime-varying conditions embedded onto the sequence of data using thecorresponding set of filter coefficients to provide a noise compensatedsequence of data.
 2. The communications receiver of claim 1, wherein thenoise analyzer comprises: a sampling module configured to sample a firstportion of the sequence of data to provide a sampled sequence of data; atime domain spectral characterization module configured to spectrallycharacterize the sampled sequence of data in a time domain to provide atime domain spectral characterization; a modify time domain spectralcharacterization module configured to modify the time domain spectralcharacterization in the time domain to provide the modified sequence ofdata; and a interference and/or distortion characterization moduleconfigured to analyze the composition of the one or more time-varyingconditions based upon at least one of a time domain spectralcharacterization information signal and a modified time domain spectralcharacterization information signal, the time domain spectralcharacterization information signal including statistical metrics of thesampled sequence of data and the modified time domain spectralcharacterization information signal including statistical metrics of thetime domain spectral characterization.
 3. The communications receiver ofclaim 2, wherein the time domain spectral characterization module isconfigured to determine an autocorrelation function of the sampledsequence of data to provide an autocorrelation matrix as the time domainspectral characterization.
 4. The communications receiver of claim 2,wherein the modify time domain spectral characterization module isconfigured to modify the time domain spectral characterization byperforming at least of: raising a noise floor, and introducing spectralcharacteristics that relate to a previously present interference and/ordistortion that are expected but that have not recently been present toprovide the modified sequence of data.
 5. The communications receiver ofclaim 1, wherein the noise analyzer comprises: a sampling moduleconfigured to sample a first portion of the sequence of data to providea sampled sequence of data; a frequency domain spectral characterizationmodule configured to spectrally characterize the sampled sequence ofdata in a frequency domain to provide a frequency domain spectralcharacterization; a modify frequency domain spectral characterizationmodule configured to modify the frequency domain spectralcharacterization in the frequency domain to provide a modified frequencydomain spectral characterization; a time domain spectralcharacterization module configured to characterize the modifiedfrequency domain spectral characterization in a time domain to providethe modified sequence of data; and a interference and/or distortioncharacterization module configured to analyze the composition of the oneor more time-varying conditions based upon at least one of a frequencydomain spectral characterization information signal and a modifiedfrequency domain spectral characterization information signal, thefrequency domain spectral characterization information signal includingstatistical metrics of the sampled sequence of data and the modifiedfrequency domain spectral characterization information signal includingstatistical metrics of the time domain spectral characterization.
 6. Thecommunications receiver of claim 5, wherein the frequency domainspectral characterization module is configured to transform the sampledsequence of data from the time domain to the frequency domain.
 7. Thecommunications receiver of claim 5, wherein the frequency domainspectral characterization module is configured to perform a Fast FourierTransform (FFT) upon the sampled sequence of data to provide thefrequency domain spectral characterization.
 8. The communicationsreceiver of claim 5, wherein the modify frequency domain spectralcharacterization module is configured to modify the frequency domainspectral characterization by performing at least of: raising a noisefloor, and introducing spectral characteristics that relate to apreviously present interference and/or distortion that are expected butthat have not recently been present to provide the modified sequence ofdata.
 9. The communications receiver of claim 5, wherein the time domainspectral characterization module is configured to perform an InverseFast Fourier Transform (IFFT) upon the modified frequency domainspectral characterization to provide the modified sequence of data. 10.The communications receiver of claim 1, wherein the coefficientgenerator comprises: a first filter coefficient updater corresponding toan absence of a first time-varying interference and/or distortioncondition and a second time-varying interference and/or distortioncondition; a second filter coefficient updater corresponding to apresence of the first time-varying interference and/or distortioncondition; a third filter coefficient updater corresponding to apresence of the second time-varying interference and/or distortioncondition; and a fourth filter coefficient updater corresponding to apresence of the first time-varying interference and/or distortioncondition and the second time-varying interference and/or distortioncondition.
 11. The communications receiver of claim 10, wherein thecoefficient generator is configured to select the set of filtercoefficients from the first filter coefficient updater when the filtercoefficient selection signal indicates the absence of the firsttime-varying interference and/or distortion condition and the secondtime-varying interference and/or distortion condition.
 12. Thecommunications receiver of claim 10, wherein the coefficient generatoris configured to select the set of filter coefficients from the secondfilter coefficient updater when the filter coefficient selection signalindicates the presence of the first time-varying interference and/ordistortion condition.
 13. The communications receiver of claim 10,wherein the coefficient generator is configured to select the set offilter coefficients from the third filter coefficient updater when thefilter coefficient selection signal indicates the presence of the secondtime-varying interference and/or distortion condition.
 14. Thecommunications receiver of claim 10, wherein the coefficient generatoris configured to select the set of filter coefficients from the firstfilter coefficient updater when the filter coefficient selection signalindicates the presence of the first time-varying interference and/ordistortion condition and the second time-varying interference and/ordistortion condition.